コバヤシ マサカズ
教授
(先進理工学部)
http://www.waseda.jp/zaiken/fol_shokai/kobayashiken/start.htm
理工学術院(大学院先進理工学研究科)
研究所員 2010年-2013年
研究所員 2009年-2014年
研究所員 2014年-2016年
兼任研究員 2018年-2018年
兼任研究員 2018年-
研究所員 2016年-2019年
研究所員 2019年-
-1983年 | 早稲田大学 理工学部 電気工学科 |
-1988年 | 東京工業大学 工学系研究科 電子物理工学 |
工学博士 課程 東京工業大学
工学博士 東京工業大学
1988年-1989年 | 助手 |
1989年-1990年 | 客員助教授 |
1990年- | 主幹研究員 |
1991年-2000年 | 助教授 |
2000年- | 教授 |
Materials Research Society
応用物理学会
電気学会
American Insitute of Physics
IEEE
American Physical Society
工学 / 材料工学 / 無機材料・物性
工学 / 電気電子工学 / 電子・電気材料工学
複合領域 / 人間医工学 / 生体医工学・生体材料学
希望連携機関:産学連携、民間を含む他機関等との共同研究等
目的:技術相談、受託研究、共同研究
希望連携機関:産学連携、民間を含む他機関等との共同研究等
目的:技術相談、受託研究、共同研究
希望連携機関:産学連携、民間を含む他機関等との共同研究等
目的:技術相談、受託研究、共同研究
シーズ分野:ナノ・材料
研究テーマのキーワード:II−VI族化合物半導体,分子線エピタキシー,紫外線センサー
個人研究
研究テーマのキーワード:ナノ微粒子,光学的特性
個人研究
研究テーマのキーワード:肺癌,自家蛍光,分光測定
個人研究
個人研究
個人研究
Masakazu Kobayashi
Journal of Crystal Growth512p.189 - 1932019年04月-
ISSN:220248
概要:? 2019 ZnTe layers were grown on various orientation surfaces of sapphire substrates, namely c-, a-, r-, and S-planes. Single domain dominant layers were achieved by carefully controlling the substrate orientation and introducing the thin buffer layer. The substrate surfaces were annealed at approximately 1000 °C to achieve an atomically smooth surface with step-terrace structures. Single domain layers were achieved by employing the step-terrace structured substrates. A nanofacet structure of the substrate surface consisting of the r-plane and the S-plane was obtained by annealing the m-plane substrate surface. Nucleation of ZnTe occurred along the nanofacet. It was confirmed that preferential nucleation of ZnTe on the S-plane of the nanofacet took place. Nitrogen doping of the ZnTe layer was performed, with the doping efficiency confirmed as being as good as ZnTe layers prepared on GaAs substrates. This is another indication of the high crystal quality for the prepared ZnTe layer.
Aya Uruno, Masakazu Kobayashi
Physica Status Solidi (A) Applications and Materials Science2162019年01月-
ISSN:18626300
概要:? 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim CuGaTe2 layers are successfully grown on Si (001) and Mo/quartz substrates using two-step closed space sublimation (CSS). The surface morphology of the Cu2Te first layer is affected by the surface free energy of the different substrates. Cu2Te grown on Si (001) comprises hexagonal islands which are highly oriented to the (0001). Conversely, Cu2Te layers formed on Mo/quartz substrates forms a thin film. The surface morphology and the quality of the crystals in the CuGaTe2 layers are investigated. Overgrowth by CuGaTe2 of the Cu2Te islands on Si substrates is confined to the islands only and there is no nucleation on the bare substrate. On the contrary, overgrowth by CuGaTe2 on the continuous Cu2Te films on Mo/quartz substrates produces continuous thin films. Therefore, the surface morphology of the CuGaTe2 layers can be controlled by changing the substrate material because they have different surface free energies.
Uruno Aya, Kobayashi Masakazu
AIP ADVANCES査読有り8(11)p.50232018年11月-
ISSN:2158-3226
Aya Uruno, Yohei Sakurakawa, Masakazu Kobayashi
Journal of Electronic Materials査読有り47(10)p.5730 - 57342018年10月-
ISSN:3615235
概要:? 2018, The Minerals, Metals & Materials Society. AgGaTe2, AgAlTe2, CuGaTe2, and Ag(Ga,Al)Te2layers were deposited by the close spaced sublimation method. The surface morphology and crystal quality of these Te-based chalcopyrite layers were systematically evaluated. Controlling the stoichiometry of these layers grown by the closed space sublimation was very difficult because Te preferentially detached from the source materials during the sublimation process and then Te vapor leaked out from the reactor. To solve this problem, the gap between the lid and reactor boat was minimized, and the vapor was encapsulated. As a result, the crystal quality of the AgGaTe2and AgAlTe2was improved. However, the controlling stoichiometry of CuGaTe2remained difficult even after the Te vapor leakage was minimized. This behavior was attributed to the large vapor pressure difference between Cu and Te. The surface morphology of the grown AgGaTe2and CuGaTe2layers exhibited scattered grain structure, while that of AgAlTe2possessed a continuous film structure. These different surface structures contributed to differing wettability between the chalcopyrite materials and substrates. It was found that AgAlTe2exhibited a high wettability against a sapphire substrate, which promoted continuous film formation.
Aya Uruno, Masakazu Kobayashi
2017 IEEE 44th Photovoltaic Specialist Conference, PVSC 2017p.1 - 62018年05月-
概要:? 2017 IEEE. The AgGaTe2layer was formed on Ag2Te/Si structure with two different procedures by eliminating the melt-back etching. Diffusion of the Ga2Te3source material into the Ag2Te layer and formation of the AgGaTe2layer were both occurring during the growth when Ag2Te and Ga2Te3source mixture was used to form AgGaTe2. It was also clear the AgGaTe2could be formed by deposition and annealing of Ga2Te3layer on top of the Ag2Te/Si structure. Solar cells were fabricated using the p-AgGaTe2/n-Si heterojunction, and showed conversion efficiency of approximately 3%.
Aya Uruno, Masakazu Kobayashi
Physica Status Solidi (A) Applications and Materials Science査読有り216p.5922019年01月-
ISSN:18626300
概要:? 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Since its bandgap is close to optimum value, AgGaTe2is regarded as a promising material for solar cells. This paper reports the result of photoluminescence (PL) experiments on AgGaTe2thin films prepared by the two-step closed space sublimation method. In particular, the effect of by-products including Ag2Te or AgGa5Te8on PL properties of AgGaTe2is investigated. The radiative recombination process is also explored. PL measurements of thin films are performed by changing the excitation intensity and measured temperature. It is confirmed that the emission band probably derived from defects and impurities exists near 1.02 eV and the emission band derived from free exciton (FE) exists around 1.32 eV, and the variation of FE emission intensity is affected by the Ag/Ga ratio in AgGaTe2. It is also investigated that the activation energy (EA) of the FE emission is about 7.8 meV.
Xianfeng Zhang, Akira Yamada, Masakazu Kobayashi
Physica Status Solidi (A) Applications and Materials Science2142017年10月-
ISSN:18626300
概要:? 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Molecular beam epitaxy was used to fabricate Ag(In,Ga)Se2(AIGS) thin films. To improve the diffusion of Ag, high-temperature deposition and high-temperature annealing methods were applied to fabricate AIGS films. The as-grown AIGS thin films were then used to make AIGS solar cells. We found that grain size and crystallinity of AIGS films were considerably improved by increasing the deposition and annealing temperature. For high-temperature deposition, temperatures over 600 °C led to decomposition of the AIGS film, desorption of In, and deterioration of its crystallinity. The most appropriate deposition temperature was 590 °C and a solar cell with a power conversion efficiency of 4.1% was obtained. High-temperature annealing of the AIGS thin films showed improved crystallinity as annealing temperature was increased and film decomposition and In desorption were prevented. A solar cell based on this film showed the highest conversion efficiency of 6.4% when annealed at 600 °C. When the annealing temperature was further increased to 610 °C, the performance of the cell deteriorated due to loss of the out-of-plane Ga gradient.
Xianfeng Zhang, Masakazu Kobayashi
IEEE Journal of Photovoltaics7p.1426 - 14322017年09月-
ISSN:21563381
概要:? 2011-2012 IEEE. Ag(In, Ga)Se2(AIGS) thin films were deposited by a modified three-stage method, using a molecular beam epitaxy apparatus. The influence of sodium on the properties of AIGS films was investigated, using Mo-coated soda-lime-glass (SLG) and quartz as substrates. A sodium concentration gradient was observed along the thickness direction of the AIGS film. This resulted from sodium diffusion from the SLG substrate. No sodium was observed in the AIGS film fabricated on the quartz substrate. The grain size and crystallinity of AIGS increased upon sodium doping. Photoluminescence (PL) experiments on the AIGS film showed that exponentially tailed donor states introduced by indium atoms were passivated by sodium. This led to free excitons being observed in the PL spectrum. Potential fluctuation was used to explain the emission spectra of both sodium-containing and sodium-free samples. The donor and acceptor levels included in the quasi-donor-acceptor pair recombination were observed at approximately 35 meV interstitial defect (GaAg) and 100 meV (VSe), respectively. Solar cell performance was significantly improved by sodium doping, probably because of defect passivation.
Yohei Sakurakawa, Aya Uruno, Masakazu Kobayashi
Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics査読有り35(4)p.1062017年07月-
ISSN:21662746
概要:? 2017 American Vacuum Society. Nucleation of Cu-Te layers was performed by the closed space sublimation method using various source materials, source temperatures, and Si substrates with different surface orientations. The objective was to produce nuclei layers with high quality for use as nucleation centers for CuGaTe2. The grown samples were evaluated by x-ray diffraction and scanning electron microscopy. Cu2Te deposits were obtained using either a CuTe or Cu2Te source, but the latter gave a higher area coverage of Cu2Te nuclei. Highly oriented nuclei were obtained when they were grown on Si (001) at a source temperature of 640 °C and substrate temperature of 590 °C. When the source temperature was raised to 750 °C and the corresponding substrate temperature was 700 °C, nonuniform but highly oriented nuclei were obtained. Both nuclei layers exhibited a strong preference for (0001) orientation. The crystallographic features of the Cu2Te nuclei formed on Si (111) were similar to those of the Cu2Te nuclei formed on Si (001).
Wei Che Sun, Taizo Nakusu, Keisuke Odaka, Masakazu Kobayashi, Toshiaki Asahi
Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics査読有り35(4)2017年07月-
ISSN:21662746
概要:? 2017 American Vacuum Society. ZnTe electro-optic waveguide device has a great potential for the practical applications. The introduction of low Mg% cladding layer to the ZnMgTe/ZnTe/ZnMgTe waveguide structure was performed to circumvent the effect of large lattice mismatch between ZnMgTe and ZnTe, and to improve the crystallographic properties. Various two-step index ZnTe waveguide structures were fabricated by molecular beam epitaxy. The structure with 0.1 μm (Mg 9%) interlayer and 0.6 μm (Mg 26%) cladding layer showed significant defect density reduction compared to the single-step index ZnTe waveguide (Mg 20%) due the much smaller lattice mismatch between the ZnTe core layer and the ZnMgTe interlayer. However, the average Mg content of ZnMgTe layers needs to be carefully controlled to prevent the drop of the optical confinement.
Taizo Nakasu, W. Sun, M. Kobayashi, T. Asahi
Journal of Crystal Growth査読有り468p.635 - 6372017年06月-
ISSN:220248
概要:? 2016 Elsevier B.V. Zinc telluride layers were grown on highly-lattice-mismatched sapphire substrates by molecular beam epitaxy, and their crystallographic properties were studied by means of X-ray diffraction pole figures. The crystal quality of the ZnTe thin film was further studied by scanning electron microscopy, X-ray rocking curves and low-temperature photoluminescence measurements. These methods show that high-crystallinity (111)-oriented single domain ZnTe layers with the flat surface and good optical properties are realized when the beam intensity ratio of Zn and Te beams is adjusted. The migration of Zn and Te was inhibited by excess surface material and cracks were appeared. In particular, excess Te inhibited the formation of a high-crystallinity ZnTe film. The optical properties of the ZnTe layer revealed that the exciton-related features were dominant, and therefore the film quality was reasonably high even though the lattice constants and the crystal structures were severely mismatched.
Xianfeng Zhang, Masakazu Kobayashi, Akira Yamada
ACS Applied Materials and Interfaces9p.16215 - 162202017年05月-
ISSN:19448244
概要:? 2017 American Chemical Society. The structural and electrical properties of the junction at Ag(In,Ga)Se2AIGS/Mo, and Cu(In,Ga)Se2CIGS/Mo layers were characterized. The region between the CIGS and Mo featured a MoSe2layer with a layered hexagonal structure and thickness of 10-15 nm. The c-axis of the MoSe2was oriented perpendicular to the Mo layer, and the c -value was 12.6 ?. However, no such layer was observed at the interface between AIGS and Mo. This result was also confirmed by energy-dispersive X-ray spectrometry and X-ray diffraction measurements of the MoSe2layer. The CIGS/Mo with a MoSe2layer formed an ohmic contact, while the AIGS/Mo without the MoSe2layer formed a Schottky contact. This Schottky contact showed a barrier height of 0.8 ± 0.02 eV, a nonideality factor of 1.5 ± 0.1, and a series resistance of 370 ± 8 ω. A schematic band diagram of the AIGS/Mo junction was constructed on the basis of the above results.
Xianfeng Zhang, Masakazu Kobayashi
IEEE Photonics Journal92017年04月-
ISSN:19430655
概要:? 2009-2012 IEEE. Ag(In, Ga)Se2(AIGS) has been considered as a promising candidate material for the top cell of chalcopyrite-based tandem solar cells. In this work, the process of (AIGS) film growth by a three-stage molecular beam epitaxy method is studied. The diffusion of silver and grain growth of AIGS films from the first stage-deposited (In, Ga)2Se3is investigated. Energy dispersive spectroscopy mapping is used to reveal the distribution of silver in the film during each stage of the deposition process. A sharp silver accumulation at the surface of the film at the early stage of the deposition process is observed. This has led to the formation of a silver-rich phase, which gradually diffused into the film to produce a homogeneous distribution. X-ray diffraction results illustrate the phase changes of AIGS films. Based on the result, a growth model for AIGS films from the first stage to the second stage is suggested as (In, Ga)2Se3→ Ag9(In, Ga)Se6at the surface and (In, Ga)2Se3at the bottom of the film → silver-rich AIGS film. During the third stage, the silver-rich film was converted to silver-poor film. The performance of AIGS solar cells fabricated from various samples was compared, and a highest efficiency of 7.1% was obtained.
Taizo Nakasu, Wei Che Sun, Masakazu Kobayashi, Toshiaki Asahi
Journal of Electronic Materials査読有り46(4)p.2248 - 22532017年04月-
ISSN:3615235
概要:? 2016, The Minerals, Metals & Materials Society. ZnTe thin films on sapphire substrate with nanofaceted structure have been studied. The nanofaceted structure of the m-plane (10-10) sapphire was obtained by heating the substrate at above 1100°C in air, and the r-plane (10-12) and S-plane (1-101) were confirmed. ZnTe layers were prepared on the nanofaceted m-plane sapphire substrates by molecular beam epitaxy (MBE). The effect of the nanofaceted structure on the orientation of the thin films was examined based on x-ray diffraction (XRD) pole figures. Transmission electron microscopy (TEM) was also employed to characterize the interface structures. The ZnTe layer on the nanofaceted m-plane sapphire substrate exhibited (331)-plane orientation, compared with (211)-plane without the nanofaceted structure. After thermal treatment, the m-plane surface vanished and (211) layer could not be formed because of the lack of surface lattice matching. On the other hand, (331)-plane thin film was formed on the nanofaceted m-plane sapphire substrate, since the (111) ZnTe domains were oriented on the S-facet. The orientation of the ZnTe epilayer depended on the atomic ordering on the surface and the influence of the S-plane.
Aya Uruno, Masakazu Kobayashi
Physica Status Solidi (A) Applications and Materials Science査読有り214(1)2017年01月-
ISSN:18626300
概要:? 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim AgGaTe2layers were prepared on Si substrates by a closed space sublimation method using a mixed powder source of Ag2Te and Ga2Te3. Ag2Te buffer layer deposition was introduced to eliminate melt-back etching. The effect of the molar ratio of Ag2Te and Ga2Te3in the mixed source on the crystallinity of the AgGaTe2layer was investigated. The composition and the phase of the layer was found to change depending on the molar ratio in the deposits, which could be controlled by the source molar ratio along with the Ag2Te buffer layer thickness. It was confirmed that (112) oriented uniform AgGaTe2layer with an abrupt interface between AgGaTe2and Si was formed after those parameters were tuned. The obtained layer exhibited the acceptor concentration of around 2.5 × 1016cm-3. A solar cell was fabricated using the p-AgGaTe2/n-Si heterojunction, and exhibited a conversion efficiency of 1.15%.
Taizo Nakasu, Wei Che Sun, Masakazu Kobayashi
Japanese Journal of Applied Physics562017年01月-
ISSN:214922
概要:? 2017 The Japan Society of Applied Physics. Domain structures of ZnTe layers grown on a-plane sapphire substrates were investigated by changing the crystallographic properties of the surface and interface. Pole figure images were obtained and we investigated the domain structure in the grown film and the orientation relationships between films and substrates. It was confirmed that two kinds of {111} domains were oriented by annealing the buffer layer at 350 °C, while the (100) domain was obtained by annealing the buffer layer at 300 °C. From the results of the rocking curve measurement, the introduction of a step-Terrace surface through the high-Temperature treatment of the substrate resulted in an improved crystallographic quality. However, it did not affect the domain structure in the layer. The introduction of an off-Angle on the substrate surface resulted in the formation of a single (111) domain layer. These crystallographic features were mainly affected by the surface atom arrangement of the sapphire substrate and its chemical nature.
T. Nakasu, W. Sun, M. Kobayashi
Japanese Journal of Applied Physics査読有り56p.155052017年00月-
Shunya Taki, Yuto Umejima, Aya Uruno, Xianfeng Zhang, Masakazu Kobayashi
16th International Conference on Nanotechnology - IEEE NANO 2016p.699 - 7022016年11月-
概要:? 2016 IEEE. Cu2ZnSn(S,Se)4(CZTSSe) is a compound semiconductor which replaces a part of S in the CZTS crystal by Se. The bandgap varies from 1.05 eV to 1.51 eV depending on the mole ratio between S and Se. In this paper, CZTSSe thin films were prepared by the selenidation of CZTS film, and the Se mole ratio was tuned by changing annealing conditions. The film quality of the obtained CZTSSe was characterized by X-ray diffraction (XRD) and Hall measurements. It was revealed that both the supply of Se vapor pressure and the annealing temperature of CZTS were controlling parameters for the selenidation of the film. The crystal quality of CZTSSe was also influenced by the supply of Se vapor pressure.
Aya Uruno, Masakazu Kobayashi
Conference Record of the IEEE Photovoltaic Specialists Conference2016-Novemberp.524 - 5292016年11月-
ISSN:1608371
概要:? 2016 IEEE. The AgGaTe2layer was formed on Ag2Te/Si structure with two different procedures by eliminating the melt-back etching. Diffusion of the Ga2Te3source material into the Ag2Te layer and formation of the AgGaTe2layer were both occurring during the growth when Ag2Te and Ga2Te3source mixture was used to form AgGaTe2. It was also clear the AgGaTe2could be formed by deposition and annealing of Ga2Te3layer on top of the Ag2Te/Si structure. Solar cells were fabricated using the p-AgGaTe2/n-Si heterojunction, and showed conversion efficiency of approximately 3%.
Xingfeng Zhang, Masakazu Kobayashi
2016 Progress In Electromagnetics Research Symposium, PIERS 2016 - Proceedingsp.2306 - 23092016年11月-
概要:? 2016 IEEE. Cu2ZnSnS4(CZTS) precursor was fabricated from a CZTS nano crystal ink, which was obtained by a ball-milling method. The precursor was then annealed in the sulfur atmosphere. The growth mechanism of CZTS was studied in this work. It was found that with the extension of annealing time, the grain size as well as the crystallinity was improved significantly. And growth of grains from domain area of CZTS nano particles was observed. The samples experienced a decomposition process during the annealing. Secondary phases, such as ZnS, SnS, CuS and CuSnS3, were detected at the beginning of annealing process. However, with the increase of annealing time, the secondary phases recombined to form uniform CZTS film, which lead to the growth of grain size and improvement of crystallinity. The growth mechanism of CZTS films during the annealing process was concluded as: CZTS(Nanoparticle)→(Cu2S, ZnS, SnxS)→CZTS (large grains).
Taizo Nakasu, Shota Hattori, Wei Che Sun, Masakazu Kobayashi
Physica Status Solidi (B) Basic Research253p.2265 - 22692016年11月-
ISSN:3701972
概要:? 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ZnTe/sapphire heterostructures have attracted attention for their suitable properties as a terahertz wave detector material. In this study, we focused on the selective growth of ZnTe on SiO2-masked sapphire substrates by molecular beam epitaxy (MBE). When ZnTe was grown at a high temperature (=350 °C), low growth rate (≦ 0.3 μm h-1), and low JTe/JZnflux ratio (≦ 0.83) compared with the conventional film growth conditions, the formation of ZnTe nuclei on the SiO2mask was avoided. The Te flux intensity significantly affected the selectivity of ZnTe growth. The selective growth of ZnTe on sapphire was revealed to be limited by the desorption of Te adatoms from the SiO2.
Taizo Nakasu, Takayuki Aiba, Sotaro Yamashita, Shota Hattori, Takeru Kizu, Wei Che Sun, Kosuke Taguri, Fukino Kazami, Yuki Hashimoto, Shun Ozaki, Masakazu Kobayashi, Toshiaki Asahi
Journal of Electronic Materials45p.4742 - 47462016年10月-
ISSN:3615235
概要:? 2016, The Minerals, Metals & Materials Society. Zinc telluride (ZnTe) epilayers were grown on S-plane (10 1 ? 1) sapphire substrates by molecular beam epitaxy, and the epitaxial relationships between the two were compared with data previously obtained for layers grown on c-plane (0001), m-plane (10 1 ? 0) substrates, and r-plane (1 1 ? 02). The crystallographic relationship between the (111) plane of the ZnTe layer and (0001) plane of the substrate was studied using x-ray diffraction pole figure measurements. It was confirmed that two kinds of {111} oriented domains were formed on the S-plane substrate, and the dominant domain was (111)-oriented. Layers grown on S-plane substrate and on m-plane substrate exhibited the same epitaxial relationship, while the epitaxial relationship of the layer grown on the c-plane substrate exhibited a 60° rotation. These findings would be applicable to control the orientation of ZnTe epilayer surface for various device applications and for various physical property characterizations.
Aya Uruno, Masakazu Kobayashi
Journal of Electronic Materials45p.4692 - 46962016年09月-
ISSN:3615235
概要:? 2016, The Minerals, Metals & Materials Society. AgGaTe2layers were successfully grown on Si substrates by the close-spaced sublimation method. The Si substrates were confirmed to be etched during AgGaTe2layer growth when the layer was grown directly on the substrate. To eliminate melt-back etching, a buffer layer of Ag2Te was introduced. It was found that the Ag2Te buffer layer changed into the AgGaTe2layer during the growth process, and a uniform AgGaTe2layer with an abrupt interface was formed. Both the diffusion of Ga into Ag2Te and the growth of AgGaTe2occurred simultaneously. It was confirmed that uniform AgGaTe2layers could be formed without any traces of the Ag2Te layer or melt-back etching by tuning the growth parameters. A solar cell was also fabricated using the p-AgGaTe2/n-Si heterojunction. This solar cell showed conversion efficiency of approximately 3%.
Wei Che Sun, Fukino Kazami, Jing Wang, Taizo Nakasu, Shota Hattori, Takeru Kizu, Yuki Hashimoto, Masakazu Kobayashi, Toshiaki Asahi
Japanese Journal of Applied Physics552016年08月-
ISSN:214922
概要:? 2016 The Japan Society of Applied Physics. A ZnMgTe/ZnTe electro-optic (EO) waveguide has great potential to be utilized for practical applications. A low-dislocation ZnMgTe/ZnTe waveguide can be fabricated when the cladding layer thickness is below 20-fold the calculated critical layer thickness (CCLT × 20). To improve optical confinement, a waveguide with a thicker cladding layer or a higher Mg% should be considered. However, the device performance might be affected because of crystal quality deterioration since the lattice mismatch between MgTe and ZnTe was around 4.1%. In this study, optical confinement and propagation loss were examined by changing the dimensions of the ZnMgTe/ZnTe waveguide structure. The propagation loss, EO characteristics, and crystal quality of the fabricated waveguides were mainly studied. A waveguide with a cladding layer thickness of around 1.5-fold the 1/e penetration depth of the evanescent wave (dp1/e × 1.5, corresponding to CCLT × 100) showed better optical properties than other waveguides, although its interface defect density was reasonably high.
T. Nakasu, T. Kizu, W. Sun, F. Kazami, M. Kobayashi, T. Asahi
2016 Compound Semiconductor Week, CSW 2016 - Includes 28th International Conference on Indium Phosphide and Related Materials, IPRM and 43rd International Symposium on Compound Semiconductors, ISCS 20162016年08月-
概要:? 2016 IEEE. ZnTe thin films were grown on m-plane sapphire substrates with nano-faceted structure by MBE. The growth process of the ZnTe thin film was analyzed by AFM. The influence of the nano-facet on the crystal quality of the epilayer was studied by means of XRD pole figure and PL measurements. It was confirmed that (331)-plane ZnTe layer was formed on the m-plane sapphire substrate with nano-faceted structure and the ZnTe epilayer grown of the nano-facet structure exhibited the single domain structure with high optical properties.
Taizo Nakasu, Shota Hattori, Takeru Kizu, Wei Che Sun, Fukino Kazami, Yuki Hashimoto, Masakazu Kobayashi, Toshiaki Asahi
Physica Status Solidi (C) Current Topics in Solid State Physics13p.435 - 4382016年07月-
ISSN:18626351
概要:Copyright ? 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim ZnTe epilayers were grown on R -plane (Formula presented.) and S -plane (Formula presented.) sapphire substrates by molecular beam epitaxy, and the crystal orientation and the optical property were studied. The crystal orientation of ZnTe layers on sapphire substrates was studied using X-ray diffraction pole figure measurements. It was confirmed that (111)-oriented domains were formed on the R -plane as well as on the S -plane substrate. Layers grown on R -plane exhibited higher film quality. From the low-temperature photoluminescence, emissions caused by ZnTe exciton were observed. (? 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).
Aya Uruno, Yuji Takeda, Tomohiro Inoue, Masakazu Kobayashi
Physica Status Solidi (C) Current Topics in Solid State Physics13p.413 - 4162016年07月-
ISSN:18626351
概要:Copyright ? 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim Ag(Ga,Al)Te2layers were grown by the closed space sublimation method on c -plane sapphire substrates. The source used was AgAlTe2/AgGaTe2mixture or AgAlTe2/Ga2Te3mixture. The crystallographic property of Ag(Ga,Al)Te2layers was analyzed by X-ray diffraction (XRD). XRD spectra of layers exhibited very strong 112 diffraction peaks regardless of the variation of the source material mixture. In addition to crystallographic characterizations, optical properties of the Ag(Ga,Al)Te2layer were evaluated through transmittance measurements. The bandgap energy was decreased when the source mole ratio of Al to Ga was decreased. It was revealed that control regulation of x composition of Ag(Ga1-x,Alx)Te2was feasible by varying the source mole ratio Al/(Ga+Al). (? 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim).
Fukino Kazami, Wei Che Sun, Kosuke Taguri, Taizo Nakasu, Takayuki Aiba, Sotaro Yamashita, Shota Hattori, Takeru Kizu, Masakazu Kobayashi, Toshiaki Asahi
Physica Status Solidi (B) Basic Research253p.635 - 6392016年04月-
ISSN:3701972
概要:? 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. ZnMgTe/ZnTe waveguide is a high potential electro-optical device. Thick and high Mg composition cladding layers are required for high optical performance waveguides. However, adding Mg would increase the lattice mismatch between ZnMgTe and ZnTe which would cause dislocation defects and generate asperities at interfaces. In this article, influence of the lattice mismatch strain to the waveguide surface morphology was studied. Waveguide structures were prepared by molecular beam epitaxy. The surface morphologies were observed using atomic force microscope and propagation loss of the waveguides were studied. Total of 0.5-0.7μm asperities were observed on the surface of waveguides with 20% of Mg composition and 1.2μm of the total cladding layer thickness. The asperities on the surface became larger (1.0-1.2μm) when the Mg composition increased to 40%. The propagation loss of the waveguide was suppressed to 7dB by tuning the growth parameters and the resulting interface roughness.
Taizo Nakasu, Takeru Kizu, Sotaro Yamashita, Takayuki Aiba, Shota Hattori, Wei Che Sun, Kosuke Taguri, Fukino Kazami, Yuki Hashimoto, Shun Ozaki, Masakazu Kobayashi, Toshiaki Asahi
Journal of Electronic Materials45p.2127 - 21322016年04月-
ISSN:3615235
概要:? 2016, The Minerals, Metals & Materials Society. ZnTe/sapphire heterostructures were focused, and ZnTe thin films were prepared on highly mismatched sapphire substrates by molecular beam epitaxy. A sapphire substrate possessing an atomically-smooth step-terrace structure was used to improve the crystallinity and morphology of the produced ZnTe film. The growth mode of the ZnTe thin film on a sapphire substrate with an atomically-smooth step-terrace structure was found to shift to a two-dimensional growth mode, and a ZnTe thin film possessing a flat surface was obtained. The crystallographic properties of the ZnTe film suggested that the resulting layer consisted of a single (111)-oriented domain. The photoluminescence property was also improved, and the interface lattice alignment between the ZnTe and sapphire was also affected by the atomically-smooth step-terrace structure.
Wei Che Sun, Fukino Kazami, Jing Wang, Taizo Nakasu, Shota Hattori, Takeru Kizu, Yuki Hashimoto, Masakazu Kobayashi, Toshiaki Asahi
MRS Advances1p.1721 - 17272016年01月-
概要:? 2016 Materials Research Society. ZnMgTe(Cladding)/ZnTe(Core)/ZnMgTe(Cladding) thin film waveguide had been grown by molecular beam epitaxy (MBE) and presented a great potential to be a high performance Electro-optical (EO) modulator. For a low propagation loss ZnMgTe/ZnTe waveguide, thick cladding layer with high Mg composition (Mg %) is needed. However, the in-plane lattice mismatch of the fabricated device with high Mg % and thick cladding layer was large. It might cause the cladding/core interface roughness and asperities due to the misfit dislocation, and degrade the device performance. Because EO property of waveguide device is primarily influence by the structure thickness, the device efficiency improvement in this study was only considered to reduce the defects asperities that would cause propagation loss without decreasing the Mg % or the total thickness of the cladding layers. Therefore, we introduced a low Mg % layer between the cladding and the core layer to circumvent the effect of large lattice mismatch. The in-plane lattice mismatch of the devices was monitored using reciprocal space mapping, and surface morphologies were also observed using atom force microscope. The two-step index ZnMgTe/ZnTe waveguide had shown to have lower degree of relaxation compared to that of single-step index waveguide device with close Mg % and cladding layer thickness. Therefore, the crystal degradation of the two-step-index waveguide caused by lattice mismatch was successfully suppressed by introduction extra low Mg % layers. The morphologies of the two kinds of waveguide structures have similar surface asperities, which indicated the extra inserted layers did not produce additional large scale asperities at the interfaces that would increase the propagation loss.
T. Nakasu, W. Sun, M. Kobayashi, T. Asahi
Journal of Crystal Growth査読有り(11)p.352016年00月-
Aya Uruno, Ayaka Usui, Tomohiro Inoue, Yuji Takeda, Masakazu Kobayashi
Journal of Electronic Materials44p.3013 - 30172015年09月-
ISSN:3615235
概要:? 2015, The Minerals, Metals & Materials Society. AgGaTe2, AgAlTe2, and Ag(Ga,Al)Te2layers were grown by the closed-space sublimation method on c-plane sapphire substrates. The crystallographic properties of the AgGaTe2and AgAlTe2layers were then analyzed by x-ray diffraction (XRD). Very strong 112 diffraction peaks were observed in the XRD spectra of both layers, and it was clear the (112) orientation was predominant in both layers. The orientation and domain structure of the AgAlTe2layer were carefully analyzed by XRD pole-figure measurement, and the effect of substrate surface atomic arrangement on the crystallinity of the AgAlTe2layer was investigated. On the basis of the pole-figure image, six types of {112} domain were confirmed in the layer, and [$$ \bar{1} $$1? 10] in one domain was regarded as aligned with the sapphire’s a-axis when the layer was formed on the c-plane sapphire substrate surface. In addition to crystallographic characterization, the optical properties of the Ag(Ga,Al)Te2layer were evaluated on the basis of transmittance measurements. The optical bandgap, derived from the transmittance spectrum, was approximately 2.0 eV. This value was between the bandgap values of AgGaTe2and AgAlTe2. These results showed that an alloy of AgGaTe2and AgAlTe2had been grown successfully.
T. Nakasu, T. Aiba, S. Yamashita, S. Hattori, W. Sun, K. Taguri, F. Kazami, M. Kobayashi, T. Asahi
Journal of Crystal Growth425p.191 - 1942015年07月-
ISSN:220248
概要:? 2015 Elsevier B.V. All rights reserved. ZnTe epilayers were grown on transparent a-plane (11-20) sapphire substrates by molecular beam epitaxy (MBE). The insertion of a lowerature nucleated buffer layer was carried out, and the influence of the buffer layer annealing prior to the film growth on crystallographic properties of the epilayer was investigated. Pole figure imaging and wide-range reciprocal space mapping (RSM) measurements were used to study the domain distribution within the layer, and epitaxial relationships between the ZnTe thin films and the sapphire substrates. The orientation of ZnTe domains formed on a-plane sapphire substrates was controlled by the annealing condition of the buffer layer. Two different {111} domains were formed from the sample the buffer layer was annealed at 350°C, while (100) layers were obtained from the sample the buffer layer was annealed at 300°C. These crystallographic features were probably originated from the atom arrangements of ZnTe and sapphire at the interface.
Aya Uruno, Ayaka Usui, Yuji Takeda, Tomohiro Inoue, Masakazu Kobayashi
Physica Status Solidi (C) Current Topics in Solid State Physics12p.508 - 5112015年06月-
ISSN:18626351
概要:? 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. The AgGaTe2layer growth was performed by the closed space sublimation method on the Mo/glass substrate. The Ag2Te buffer layer was inserted between AgGaTe2and Mo layers, to improve the quality of grown layers. Crystallographic properties were analyzed by x-ray diffraction (XRD), and the surface morphologies were analyzed by scanning electron microscopy (SEM). The Ag2Te layer grown on the Mo/glass exhibited a membrane filter structure from the SEM observation. XRD spectra of layers grown with and without the buffer layer were compared. The AgGaTe2layer with the Ag2Te buffer layer exhibited peaks originating from AgGaTe2, and a very strong diffraction peak of 112 was observed. On the other hand, it was cleared that the layer grown without the buffer layer exhibited no strong peaks associated with AgGaTe2, but Ga-Te compounds. From this, crystallographic properties of the AgGaTe2layer were drastically improved by the insertion of the Ag2Te buffer layer. Moreover, the surface morphology exhibited a smooth surface when the Ag2Te buffer layer was inserted. The nucleation site density of AgGaTe2was probably increased since the membrane filter structure exhibited numbers of kinks at the edge. Chemical reaction between Ga and Mo was also eliminated. It was cleared that the insertion of the buffer layer and its surface morphology were an important parameter to grow high quality AgGaTe2layers.
Taizo Nakasu, Takayuki Aiba, Sotaro Yamashita, Shota Hattori, Takeru Kizu, Wei Che Sun, Kosuke Taguri, Fukino Kazami, Masakazu Kobayashi
Japanese Journal of Applied Physics542015年01月-
ISSN:214922
概要:? 2015 The Japan Society of Applied Physics. ZnTe epilayers were grown on r-plane (11?02) and n-plane (112?3) sapphire substrates by molecular beam epitaxy. The ZnTe domain distribution in the layer and the influence of the substrates' c-plane location on the orientation of the epilayer were studied by means of X-ray diffraction pole figure measurements. Computer simulation was used to analyze the diffraction patterns. The (100)-plane ZnTe was formed on the r-plane substrate whereas two different {111}-plane mixed with the (511) domain were formed on n-plane substrate, respectively. The orientation of ZnTe layers on r-plane sapphire substrates could not change even by varying the buffer layer growth condition. From these results, it was revealed that the relationship of the sapphire c-plane and the (111) ZnTe strongly affected the orientation of the film. ZnTe layers grown on n-plane sapphire substrates, on the other hand, exhibited different relationships and (111) of ZnTe was not aligned to the sapphire c-plane.
Aya Uruno, Ayaka Usui, Masakazu Kobayashi
Journal of Electronic Materials43p.2874 - 28782014年01月-
ISSN:3615235
概要:AgGaTe2and AgAlTe2layers were grown on a-plane sapphire substrates by closed-space sublimation. These compounds replace Cd in CdTe with group I and III elements, and are, hence, expected to be ideal novel candidate materials for solar cells. The grown layers were confirmed to be stoichiometric AgGaTe2and AgAlTe2by x-ray diffraction (XRD). The AgAlTe2layers had strong preference for the (112) orientation. The XRD spectrum of the AgGaTe2layer was different from that of the AgAlTe2layer, and strong peaks were observed for (103) and (110) diffraction. The variation in orientations of the grown layers was analyzed in detail by use of XRD pole figures, which revealed that the AgGaTe2layers had an epitaxial relationship with the a-plane sapphire substrates. ? 2014 TMS.
Taizo Nakasu, Masakazu Kobayashi, Hiroyoshi Togo, Toshiaki Asahi
Journal of Electronic Materials43p.921 - 9252014年01月-
ISSN:3615235
概要:ZnTe epilayers have been grown on 2°-tilted m-plane 10 1 ? 0 sapphire substrates by molecular beam epitaxy. Pole figure imaging was used to study the domain distribution within the layer, and the pole figures of 111, 220, 004, and 422 ZnTe and 30 3 ? 0 sapphire were measured. Computer simulation was used to analyze the symmetry of the diffraction patterns seen in the pole figure images. Stereographic projections were also compared with the pole figures of 422 and 211 ZnTe, confirming that single-domain (211)-oriented ZnTe epilayers had been grown on the 2°-tilted m-plane sapphire substrates. Although differences in crystal structure and lattice mismatch were severe in these heterostructures, precise control of the substrate surface's lattice arrangement would result in the formation of high-quality epitaxial layers. ? 2014 TMS.
A. Uruno, A. Usui, M. Kobayashi
Journal of Applied Physics1162014年01月-
ISSN:218979
概要:? 2014 AIP Publishing LLC. AgAlTe2layers were grown on a- and c-plane sapphire substrates using a closed space sublimation method. Grown layers were confirmed to be single phase layers of AgAlTe2by X-ray diffraction. AgAlTe2layers were grown to have a strong preference for the (112) orientation on both kinds of substrates. The variation in the orientation of grown layers was analyzed in detail using the X-ray diffraction pole figure measurement, which revealed that the AgAlTe2had a preferential epitaxial relationship with the c-plane sapphire substrate. The atomic arrangement between the (112) AgAlTe2layer and sapphire substrates was compared. It was considered that the high order of the lattice arrangement symmetry probably effectively accommodated the lattice mismatch. The optical properties of the grown layer were also evaluated by transmittance measurements. The bandgap energy was found to be around 2.3eV, which was in agreement with the theoretical bandgap energy of AgAlTe2.
Aya Uruno, Ayaka Usui, Masakazu Kobayashi
Japanese Journal of Applied Physics532014年01月-
ISSN:214922
概要:AgGaTe2 layers were grown on a- and c-plane sapphire substrates by a closed-space sublimation method. Various samples have been prepared with various source temperatures, holding times, and temperature differentials. In this study, the variation of source temperature was primarily aimed at improving the stoichiometry of the film. The grown films were evaluated by X-ray diffraction (XRD) measurements. When the sample was grown at a high temperature, namely, above 800 °, the formation of Ag-Te compounds was observed. The Ag-Te compounds exhibited a high degree of crystallinity when the layer was grown on c-plane sapphire substrates. By using a pole figure, it was possible to study the orientation of the film, and AgGaTe2 layers were shown to have a preferential orientation in the (103) on a-sapphire.? 2014 The Japan Society of Applied Physics.
Ayaka Usui, Aya Uruno, Masakazu Kobayashi
Physica Status Solidi (C) Current Topics in Solid State Physics11p.1190 - 11932014年01月-
ISSN:18626351
概要:Chalcopyrite I-III-VI2 compounds are considered as novel potential materials for solar cells. Among the variety of those compounds, CuGaTe2 and AgAlTe2 films were grown by a closed space sublimation method. Crystallinity and stoichiometry of grown films were evaluated by X-ray diffraction measurements. When CuGaTe2 powder source was used to grow CuGaTe2 films at around 840 °C of the source temperature, stoichiometric CuGaTe2could not be formed. X-ray diffraction measurements revealed that the deposited material was Cu-Ga compound. The desorption of Te was compensated by adding elemental Te in the source material. These stoichiometric CuGaTe2 films were achieved when the volume of additional Te was around twice weight of CuGaTe2. On the other hand, growth of AgAlTe2 films could be achieved when the source temperature was 800 °C, and no additional Te was introduced in the source. From X-ray diffraction measurements, it was found that these two compounds films had strong preference for the (112) orientation on the quartz substrate. ? 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Taizo Nakasu, Masakazu Kobayashi, Toshiaki Asahi, Hiroyoshi Togo
Japanese Journal of Applied Physics532014年01月-
ISSN:214922
概要:ZnTe epilayers were grown on transparent (10?10) oriented (m-plane) sapphire substrates by molecular beam epitaxy (MBE). The insertion of a lowtemperature buffer layer was carried out, and the influence of the buffer layer annealing on crystallographic properties was investigated. Pole figure imaging was used to study the domain distribution in the layer. It was shown that strongest (211)- and (100)-oriented ZnTe epilayers were formed on m-sapphire when a ZnTe buffer layer annealed at 340 ° for 5-min was inserted. Also, it was confirmed that only (211) ZnTe epilayers were formed on the 2° tilted m-plane sapphire substrate. Thus, the single domain (211) ZnTe epilayer can be grown on the m-plane sapphire using MBE.? 2014 The Japan Society of Applied Physics.
W. Sun, T. Nakasu, K. Taguri, T. Aiba, S. Yamashita, M. Kobayashi, H. Togo, T. Asahi
Physica Status Solidi (C) Current Topics in Solid State Physics11p.1252 - 12552014年01月-
ISSN:18626351
概要:ZnMgTe/ZnTe/ZnMgTe thin film waveguide with high crystal quality were grown by molecular beam epitaxy (MBE). The in-plane mismatch between the ZnMgTe cladding layers and ZnTe core layer was about 0.02% which was measured by X-ray reciprocal space mapping (RSM). It indicated that films were grown coherently with high crystal quality. The Electro-Optical characterization of waveguide was evaluated using 1.55μm polarized lights and bias applied on the waveguide device from -15 V to +15 V. The de-pendence of light phase shift passed though the waveguide on the applied voltage bias was studied. The electro-optical characterization of the waveguide device was about 7% of the theoretical calculation. It could be improved by increasing the resistance ratio between the ZnMgTe/ZnTe/ZnMgTe waveguide structure and substrate so that the electric field applied on the waveguide structure could be improved. It was indicated that the ZnMgTe/ZnTe/ZnMgTe thin film waveguide has the potential to become a high efficiency electro-optical device. ? 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Aya Uruno, Ayaka Usui, Masakazu Kobayashi
Physica Status Solidi (C) Current Topics in Solid State Physics11p.1186 - 11892014年01月-
ISSN:18626351
概要:AgGaTe2 layers were grown on a- and c-plane sapphire substrates by a closed space sublimation method with varying the source temperature. Grown films were evaluated by θ -2θ and pole figure measurements of X-ray diffraction. AgGaTe2 layers were grown to have strong preference for the (103) orientation. However, it was cleared the Ag5Te3 was formed along with the AgGaTe2 when the layer was grown on c-plane sapphire. The orientation of the film was analyzed by using the pole figure, and resulted in AgGaTe2 without Ag5Te3 layers could be grown on a-plane sapphire. (? 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Copyright ? 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Taizo Nakasu, Wei Che Sun, Sotaro Yamashita, Takayuki Aiba, Kosuke Taguri, Masakazu Kobayashi, Toshiaki Asahi, Hiroyoshi Togo
Physica Status Solidi (C) Current Topics in Solid State Physics11p.1182 - 11852014年01月-
ISSN:18626351
概要:ZnTe epilayers were grown on transparent (10-10) oriented (m -plane) sapphire substrates by molecular beam epitaxy (MBE). Pole figure imaging was used to study the domain distribution within the layer. (211)-oriented ZnTe domains were formed on m -plane sapphire. The presence of only one kind of (211) ZnTe domain formed on the 2°-tilted m -plane sapphire substrates was confirmed. Thus, single domain (211) ZnTe epilayers can be grown on the m -plane sapphire using MBE. Although differences in the crystal structure and lattice mismatch are large, precise control of the substrate surface lattice arrangement result in the formation of high-quality epitaxial layers. ? 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
T. Nakasu, S. Yamashita, T. Aiba, S. Hattori, W. Sun, K. Taguri, F. Kazami, M. Kobayashi
Journal of Applied Physics1162014年01月-
ISSN:218979
概要:? 2014 AIP Publishing LLC. The electrooptic effect in ZnTe has recently attracted research attention, and various device structures using ZnTe have been explored. For application to practical terahertz wave detector devices based on ZnTe thin films, sapphire substrates are preferred because they enable the optical path alignment to be simplified. ZnTe/sapphire heterostructures were focused upon, and ZnTe epilayers were prepared on highly mismatched sapphire substrates by molecular beam epitaxy. Epitaxial relationships between the ZnTe thin films and the sapphire substrates with their various orientations were investigated using an X-ray diffraction pole figure method. (0001) c-plane, (1-102) r-plane, (1-100) m-plane, and (11-20) a-plane oriented sapphire substrates were used in this study. The epitaxial relationship between ZnTe and c-plane sapphire was found to be (111) ZnTe//(0001) sapphire with an in-plane orientation relationship of [ 211] ZnTe//[1-100] sapphire. It was found that the (211)-plane ZnTe layer was grown on the m-plane of the sapphire substrates, and the (100)-plane ZnTe layer was grown on the r-plane sapphire. When the sapphire substrates were inclined from the c-plane towards the m-axis direction, the orientation of the ZnTe thin films was then tilted from the (111)-plane to the (211)-plane. The c-plane of the sapphire substrates governs the formation of the (111) ZnTe domain and the ZnTe epilayer orientation. These crystallographic features were also related to the atom arrangements of ZnTe and sapphire.
Taizo Nakasu, Masakazu Kobayashi, Hiroyoshi Togo, Toshiaki Asahi
Physica Status Solidi (C) Current Topics in Solid State Physics10p.1381 - 13842013年11月-
ISSN:18626351
概要:Single-crystalline and single domain ZnTe thin films are sought for high-performance terahertz wave detectors, and ZnTe/sapphire heterostructures were considered since the Electro-Optical (EO) effect could be obtained only from epilayers. ZnTe epilayers were grown on m-plane sapphire substrates by molecular beam epitaxy, and the potential of single domain epilayers was explored. Through the X-ray diffraction pole figure measurement it was confirmed that one (100) oriented ZnTe domain along with two kinds of (211) oriented domains were formed on the m-plane sapphire when the layer was grown at 340 °C. When the layer was grown at 350 °C, the (211) oriented domain dominated the film. ? 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Aya Uruno, Ayaka Usui, Masakazu Kobayashi
Physica Status Solidi (C) Current Topics in Solid State Physics10p.1389 - 13922013年11月-
ISSN:18626351
概要:AgGaTe2layers were grown on a-plane sapphire substrates by a closed space sublimation method. Various samples were prepared with varied source temperature, holding time and temperature differential. The variation of source temperature was used primarily to improve the stoichiometry of the film. Grown films were evaluated by XRD measurements. AgGaTe2layers were grown only at low source temperature (about 780 °C), and to have strong preference for the (103) orientation. By using the pole figure, it is possible to study the orientation of the film, and the substrate surface arrangement has resulted in this unique relationship. ? 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Aya Uruno, Masakazu Kobayashi
Journal of Electronic Materials42p.859 - 8622013年01月-
ISSN:3615235
概要:AgGaTe2layers were deposited on Si substrates by the closed-space sublimation method. Multiple samples were deposited with various source temperatures and holding times, and constant temperature differential. Variation of the source temperature was used primarily to improve the stoichiometry of the film. Deposited films were evaluated by the θ-2θ method of x-ray diffraction (XRD) and transmission electron microscopy. These results confirmed that the deposited films were stoichiometric (after optimizing the above parameters). From XRD, it was also clear that films deposited on Si (111) have strong preference for (112) orientation. ? 2013 TMS.
Masakazu Kobayashi, Ayaka Yagi, Sayako Hamaguchi
Proceedings of the IEEE Conference on Nanotechnology2012年11月-
ISSN:19449399
概要:Ba2ZnS3:Mn (BZS), SrGa2S4:Eu, and BaAl2S4:Eu nanoparticles phosphor materials were prepared by a break down method, namely the ball-milling method. Several-nanometer-size stoichiometric and dispersed nanoparticles were achieved. Red color phosphor material, namely BZS, was sprayed on the glass substrate. Mn doped BZS absorbs ultra violet light and emits red light peaking at around 640nm. The transparent nanoparticle layer absorbed short wavelength light and converted to long wavelength light for the Si solar cell application. ? 2012 IEEE.
Taizo Nakasu, Yuki Kumagai, Kimihiro Nishimura, Masakazu Kobayashi, Hiroyoshi Togo, Toshiaki Asahi
Applied Physics Express52012年09月-
ISSN:18820778
概要:ZnTe epilayers were grown on transparent substrates by molecular beam epitaxy. The insertion of a low-temperature buffer layer was carried out, and the influence of the buffer layer thickness and its annealing on the crystallographic property were investigated. Pole figure imaging was used to study the domain distribution in the layer. It was shown that the (111) ZnTe epilayer with the decreased number of domains could be formed on c-sapphire when a 3.5-nm-thick annealed ZnTe buffer layer was inserted. It was shown that the XRD pole figure imaging was a useful means of analyzing domain distributions in the film. ? 2012 The Japan Society of Applied Physics.
Masakazu Kobayashi, Yuki Kumagai, Toshiaki Baba, Shota Imada
Physica Status Solidi (C) Current Topics in Solid State Physics9p.1748 - 17512012年08月-
ISSN:18626351
概要:The electro-optical effect of ZnTe is recently highlighted, and various device structures utilizing ZnTe are explored. ZnTe substrates are recently commercially available, and high quality homoepitaxial layers can be grown. On the other hand, the cost of the substrate could be a concern for the practical device application. In this study, Si and Al 2O 3 substrates were used since they are widely used for many kinds of device applications. The lattice mismatch between those substrate materials and ZnTe is above 10% and those mismatch strain should be carefully considered. ZnTe layers were nucleated on chemically treated substrate surfaces. (111), (110), (211) oriented Si substrates and (0001), (11-20), and (10-10) planes of Al 2O 3 were used. By taking the pole figure data and studying the crystal symmetry of the domain, detail information associated with the formation of domains in the layer was discussed. The pole figure analysis revealed that several kinds of (110) oriented ZnTe domains rotated 60 degrees each other were formed on (110) oriented Si surface. On the other hand, preferentially oriented single domain of (111) was confirmed for the layer grown on the (0001) plane of Al 2O 3. ZnTe layers grown on (10-10) plane Al 2O 3exhibited a unique domain formation. Pole figure data combined with the conventional theta-2theta measurement indicated that (211) oriented plane of ZnTe was a dominant domain formed on the (10-10) plane Al 2O 3. These crystallographic features would be related to the interface valency as well as the interfacial bond structure. X-ray pole figure method was a useful and powerful method to study the domain formation of the severely lattice mismatched structures. ? 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Yuki Kumagai, Masakazu Kobayashi
Japanese Journal of Applied Physics512012年02月-
ISSN:214922
概要:The electro-optical (EO) effect of the ZnMgTe/ZnTe waveguide structure grown on (001) ZnTe single crystal substrates using molecular beam epitaxy (MBE) was studied. The EO properties of ZnTe were investigated by optical confinement with an electric field. The effect of the applied electric field and the rotation of polarization wave effect are discussed. ? 2012 The Japan Society of Applied Physics.
Masakazu Kobayashi
Materials Research Society Symposium Proceedings1394p.93 - 1002011年12月-
ISSN:2729172
概要:Conventional phosphor materials are doped ternary or quaternary compounds; hence it would be difficult to prepare nanoparticles of those materials by build up methods. Ba2ZnS3:Mn (BZS), SrGa2S4:Eu, and BaAl2S4:Eu nanoparticles were prepared by a break down method, namely the ball-milling method. Transmission electron microscopy (TEM) and TEM- energy-dispersive X-ray spectroscopy (EDX) measurements showed several-nanometer-size stoichiometric and dispersed nanoparticles were achieved. ZnO-coating was performed and the uniform coating layers were formed on the phosphor nanoparticles. The ZnO-coated nanoparticles exhibited an improved stability in Photoluminescence. Red color phosphor material, namely BZS, was ball-milled and sprayed on the glass substrate. Mn doped BZS absorbs ultra violet light and emits red light peaking at around 640nm. When the single crystal Si solar cell was placed under the transparent nanoparticle layer, short wavelength light was absorbed and converted to long wavelength light. ? 2012 Materials Research Society.
Y. Kumagai, S. Imada, T. Baba, M. Kobayashi
Journal of Crystal Growth323p.132 - 1342011年05月-
ISSN:220248
概要:ZnMgTe/ZnTe/ZnMgTe layered structures were grown on (0 0 1) ZnTe substrates by molecular beam epitaxy. This structure was designed to apply to waveguides in various optoelectronic devices to reduce light loss. Since the lattice mismatch between ZnTe and ZnMgTe was not negligible, the critical layer thickness (CLT) was theoretically derived. Structures with varying Mg composition and layer thickness of ZnMgTe cladding layer were grown and examined for crystal quality with respect to theoretical data. The crystal quality was investigated by means of cross sectional transmission electron microscopy (TEM) and reciprocal space mapping (RSM). Optical confinements were observed by irradiating a laser beam from one end of the sample and monitoring the transmitted light from the other end. ? 2010 Elsevier B.V. All rights reserved.
S. Imada, T. Baba, S. Sakurasawa, M. Kobayashi
Physica Status Solidi (C) Current Topics in Solid State Physics7p.1473 - 14752010年08月-
ISSN:18626351
概要:ZnMgTe/ZnTe layered structures were grown on ZnTe substrates by molecular beam epitaxy, and the crystal structures were characterized using X-ray diffraction methods. This structure would be the waveguide for various optoelectronic devices. Therefore, the crystal quality of this layered structure would be very crucial for the realization of high performance devices. ZnMgTe is lattice mismatched to ZnTe, and the increase of the ZnMgTe layer thickness or Mg mole fraction ratio would result in the crystal quality deterioration of the layered structure. The critical layer thickness (CLT) was theoretically derived, and various structures with various ZnMgTe layer thickness and Mg mole fraction were grown. The lattice mismatch strain relief and crystal quality of those samples were investigated by means of X-ray reciprocal space mapping (RSM) and cross sectional transmission electron microscopy (TEM). The dislocation formation and the lattice mismatch relaxation were confirmed for various samples and it was revealed that the calculated CLT values could be used as an appropriate guideline to design the dislocation free and high performance device structures. ? 2010 Wiley-VCH Verlag GmbH & Co. KGaA.
Savako Hamaguchi, Savako Hamaguchi, Takuma Yamamoto, Takuma Yamamoto, Masakazu Kobayashi
IDW '09 - Proceedings of the 16th International Display Workshops1p.383 - 3852009年12月-
概要:SrGa2S4:Eu has been recently widely studied. Annealing treatment in a vacuum and a H2S atmosphere is used for the improvement of the crystallinity and optical properties. H2S annealed nanoparticles showed better characterizations than vacuum annealed ones. Good samples in optical property indicate also good data in crystallinity.
Sayako Hamaguchi, Sayako Hamaguchi, Takuma Yamamoto, Takuma Yamamoto, Masakazu Kobayashi
Japanese Journal of Applied Physics482009年04月-
ISSN:214922
概要:Conventional phosphor materials are doped ternary or quaternary compounds; hence it would be difficult to prepare those nanoparticles by build up methods. Ba2ZnS3:Mn, SrGa2S4:Eu, and BaAl2S4:Eu nanoparticles were prepared by a break down method, namely ball-milling method. Transmission electron microscopy (TEM), and TEM-energy-dispersive X-ray spectroscopy (EDX) measurements showed several-nanometer-size stoichiometric and dispersed nanoparticles were achieved. The annealing was performed after the milling for those particles to cure the mechanical damages. The annealing in a vacuum at around the calcination temperature of starting materials showed the cured photoluminescence (PL). ZnO-coating was performed and the uniform coating layer of the thickness about 10nm was formed on the phosphor nanoparticles. The ZnO-coated nanoparticles exhibited an improved stability in PL. ? 2009 The Japan Society of Applied Physics.
S. Hamaguchi, S. Ishizaki, M. Kobayashi
Journal of the Korean Physical Society53p.3029 - 30322008年11月-
ISSN:3744884
概要:ZnS:Mn2+ nanoparticles and other sulpher-based ternary compound nanoparticles were achieved using a ball-milling method. Several-nanometer-sized ZnS:Mn2+ nanoparticles were achieved by comminuting materials in a solvent. Both X-ray diffraction (XRD) and transmission electron microscopy (TEM) suggested that the particles had been milled down to the nanometer size. TEM-energy-dispersive X-ray spectroscopy (TEM-EDX) suggested that the stoichiometry of the starting powder was not affected by the ball-milling process. The orange-colored luminescence originating from Mn2+ was improved by reducing the particle size to several nanometers. Red, green and blue (RGB) colored phosphors were also studied using this technique. Ba 2ZnS3:Mn (Red), SrGa2S4:Eu (Green), BaAl2S4:Eu (Blue) and phosphor materials with sizes of about several micrometers were comminuted to nanoparticles without affecting the crystal structure and the stoichiometry. Bright red, green and blue luminescence were confirmed from those nanoparticles.
A. Ichiba, M. Kobayashi
Journal of Crystal Growth301-302p.285 - 2882007年04月-
ISSN:220248
概要:The co-doping technique known as an effective method to circumvent the dopant compensation problem was applied for the molecular beam epitaxy (MBE) growth of homoepitaxial ZnTe layers. The co-doping concept is to introduce two oppositely polar atoms at the same time in a 2:1 ratio, forming metastable three-atom complexes located at adjacent crystal sites. Al donor and N acceptor were sandwiched between undoped ZnTe spacing layers. In order to reduce the beam intensity of the RF plasma excited nitrogen species, N2gas was diluted by Ar gas. From the low temperature PL spectra, the increase of the Al doping efficiency was confirmed for co-doped layers, especially co-doped using the diluted N2gas. ? 2007 Elsevier B.V. All rights reserved.
M.W. Allen, C.H. Swartz, M. Henseler, R.J. Reeves, J.B. Metson, H. Von Wenckstern, M. Grundmann, S.A. Hafield, P.H. Jefferson, P.D.C. King, T.D. Veal, C. McConville, M. Kobayashi and S.M. Durbin
Mat. Res. Soc. Symp. Proc.査読有り955E2007年00月-
C. E. Kendrick, C. E. Kendrick, R. Tilley, R. Tilley, M. Kobayashi, R. J. Reeves, R. J. Reeves, S. M. Durbin, S. M. Durbin
Materials Research Society Symposium Proceedings955p.270 - 2752006年12月-
ISSN:2729172
概要:3-D branching GaN nanowires have been grown using the intermediate and Ga-rich growth regimes of plasma assisted molecular beam epitaxy. Evidence that the growth is due to an auto-catalytic VLS process is obtained through SEM images showing droplet termination heads, the composition of which is essentially pure Ga. TEM analysis revealed a defect free crystal structure, even in the trunk to branch junction. Cathodoluminescence from the trunk of the branching nanowires produced a strong luminescence feature at 3.44 eV, while a slight decrease in energy to 3.1 eV was observed at the interface between the nanowire and epilayer or kink site. No yellow luminescence was detected, further suggesting a defect free growth. Preliminary I-V measurements give mixed results, suggesting intrinsic n-type nanowires. ? 2007 Materials Research Society.
J. Ueno, K. Ogura, A. Ichiba, S. Katsuta, M. Kobayashi, K. Onomitsu, Y. Horikoshi
Physica Status Solidi C: Conferences3p.1225 - 12282006年05月-
ISSN:16101634
概要:ZnSe/MgCdS and ZnCdS/MgCdS superlattices were grown on semi insulating (001) oriented GaAs substrates by molecular beam epitaxy (MBE). The crystal quality and optical properties were examined for both superlattices. The observed photoluminescence (PL) peak intensity of ZnCdS/MgCdS was much stronger than that of ZnSe/MgCdS while ZnSe/MgCdS showed sharper luminescence line width. The PL peak energy position was compared with the theoretical value derived from the Kronig-Penny model. The degradation of crystal quality was observed by increasing Mg content in MgCdS layer and drastic PL property degradation was observed when the Mg content in the layer exceeded a certain value. Two superlattices were applied to the UV-A sensor of the metal-semiconductor-metal (MSM) configuration. Both photodetectors exhibited a high sensitivity in the UV-A region with a sharp cut-off in the visible wave-length region; the ON-OFF ratio of sensor was about 103 for both structures. ? 2006 WILEY-VCH Verlag GmbH & Co. KGaA,.
A. Icshba, J. Ueno, K. Ogura, S. Katsuta, M. Kobayashi
Physica Status Solidi C: Conferences3p.789 - 7922006年05月-
ISSN:16101634
概要:In order to get around the high and activated n-doping levels for ZnTe, the co-doping technique known as effective method to overcome the dopant compensation was explored. The co-doping concept is to introduce two oppositely polar atoms at the same time in a 2:1 ratio, forming metastable three-atom complexes located at adjacent crystal sites. In this study, two types of deposition process were considered to place the co-dopants at the intended site, and the co-doped ZnTe:(Al, N) layers were grown on (001) oriented ZnTe substrates by molecular beam epitaxy. From the low temperature PL spectra, the increase of Al activation was confirmed by using co-doping sequences, and the activation of N dopant was also confirmed for one doping sequence even thought the doping level was maintained the same. ? 2006 WILEY-VCH Verlag GmbH & Co. KGaA,.
Shinji Ishizaki, Yusuke Kusakari and Masakazu Kobayashi
Mater. Res. Soc. Symp. Proc.829p.2221 - 22252005年00月-
Yusuke Kusakari, Shinji Ishizaki, and Masakazu Kobayashi
Mater. Res. Soc. Symp. Proc.829p.1021 - 10252005年00月-
. Ueno, M. Enami, S. Katsuta, A. Ichiba, and K. Ogura, K. Onomitsu, and Y. Horikoshi . Ueno, M. Enami, S. Katsuta, A. Ichiba, and K. Ogura, K. Onomitsu, and Y. Horikoshi
J. Cryst. Growth278p.273 - 2772005年00月-
M.Kobayashi, S. Ishizaki, and M. Uenishi
Proc. International conference on nanomaterials NANO20051p.95 - 982005年00月-
M. ENAMI, K. TSUTSUMI, F. HIROSE, S. KATSUTA and M. KOBAYASHI
physica status solidi (c)1(4)p.1038 - 10412004年03月-
Yasuhiro Ueda, Masakazu Kobayashi
Applied Optics43(20)p.3993 - 39982004年00月-
鮫島 冴映子, 小林 正和, 渋谷 潔, 星野 英久, 千代 雅子, 藤沢 武彦
日本レーザー医学会誌 = The Journal of Japan Society for Laser Medicine24(3)2003年09月-
ISSN:2886200
Masakazu Kobayashi, Rina Sawada, and Yasuhiro Ueda
IEEE Journal of Selected Topics in Quantum Electronics9(2)p.142 - 1472003年00月-
K. Tsutsumi, H. Terakado, M. Enami, and M. Kobayashi
J. Vac. Sci. Technol. B21, 1959-19622003年00月-
Masaaki ENAMI, Kazuaki TSUTSUMI, Fumiaki HIROSE, Shohei KATSUTA, and Masakazu KOBAYASHI
Jpn. J. Appl. PhysVol.42 No.9AB pp.L1047 - L10492003年00月-
M. Kobayashi, H. Terakado, R. Sawada, A. Arakawa, AND K. Sato
Phys.Stat.Solidi (b)229, 265-2682002年00月-
Masakazu Kobayashi, Kiyoshi Shibuya, Hidehisa Hoshino, and Takehiko Fujisawa
Journal of Biomedical OpticsVolume 7, Issue 4 603-6082002年00月-
M. Kobayashi, K. Shibuya, H. Hoshino, and T. Fujisawa
Proc. of 14TH WORLD CONGRESS OF THE INTERNATIONAL SOCIETY FOR LASER SURGERY AND MEDICINEp125-1292001年00月-
Hailong Zhou, A. V. Nurmikko, S. Nakamura, K. Kitamura, H. Umeya, A. Jia, M. Kobayashi, A. Yoshikawa, M. Shimotomai, Y. Kato
Journal of Applied Physics88p.4725 - 47282000年10月-
ISSN:218979
概要:Self-assembled nanocrystalline dots of CdS grown within a ZnSe host have been studied by steady state and transient optical spectroscopies. This material system features an unusually low density of the dots, into which the excitation transfer of excitons from the host has been identified. ? 2000 American Institute of Physics.
T. Kazama, F. Yasunaga, Y. Taniyasu, A. Jia, Y. Kato, M. Kobayashi, A. Yoshikawa, K. Takahashi
Physica Status Solidi (A) Applied Research180p.345 - 3502000年07月-
ISSN:318965
概要:Atomic scale characterization of cleaved surfaces of cubic GaN (c-GaN) epilayers was established in real space. Using cross-sectional scanning tunneling microscopy (XSTM), c-GaN epilayers grown on GaAs (001) by low pressure MOVPE were investigated. The analysis of STM observations revealed that the atomic arrangement of the c-GaN (11?0) surface depended on the crystal quality of the c-GaN epilayer. For high quality c-GaN regions, the STM image confirmed that the c-GaN (11?0) surface was a 1 × 1 reconstruction in analogy to GaAs. On the other hand, for poor quality c-GaN regions, a structure different from the 1 × 1 reconstruction was observed, which was the disordered structure composed of atomic rows along the growth direction. In addition, stacking faults parallel to the c-GaN (111) plane, which gave rise to hexagonal GaN inclusions in the c-GaN epilayer, were characterized in real space.
Y. Taniyasu, K. Suzuki, D. H. Lim, A. W. Jia, M. Shimotomai, Y. Kato, M. Kobayashi, A. Yoshikawa, K. Takahashi
Physica Status Solidi (A) Applied Research180p.241 - 2462000年07月-
ISSN:318965
概要:Cubic (zinc-blende) InGaN/GaN double-heterostructure LEDs were fabricated on GaAs (001) substrates. The device performance and crystal quality were investigated. The emission wavelength was controlled by the In content in the cubic InGaN active layer. The violet-blue electroluminescence was observed around 435 nm with a FWHM of 55 nm from a cubic In0.07Ga0.93N/GaN DH LED. The forward voltage was 4.9 V at 20 mA and the reverse leakage current was 5 mA at -10 V. X-ray reciprocal space mapping measurement was performed to investigate the phase purity and strain in InGaN/GaN heterostructure. The mixing of the stable hexagonal phase in the cubic GaN was observed and the hexagonal phase content was about 10%. In-situ spectroscopic ellipsometry measurement showed that most of the mixed hexagonal domains were likely to be formed in the Mg-doped GaN layer. In addition, the anisotropic lattice relaxation occurred in the InGaN active layer. The elimination of the hexagonal phase inclusions plays an important role for the realization of high performance devices.
K. Kitamura, H. Umeya, A. Jia, M. Shimotomai, Y. Kato, M. Kobayashi, A. Yoshikawa, K. Takahashi
Journal of Crystal Growth214p.680 - 6832000年06月-
ISSN:220248
概要:Self-assembled quantum dots (QDs) of CdS were grown on ZnSxSe1-x. Low-temperature photoluminescence (PL) properties of CdS QDs were studied and a blue shift was observed when the S composition in ZnSxSe1-xwas increased. This shift is related to the band line-up between ZnSxSe1-xand CdS; the band line-up is type-II. Blue-light-emitting diode (LED) structures embedded in CdS QD layers in the pn junction of ZnSe or ZnSxSe1-xwere fabricated. I-V characteristics were compared for two device structures.
M. Kobayashi, K. Kitamura, H. Umeya, A. W. Jia, A. Yoshikawa, M. Shimotomai, Y. Kato, K. Takahashi, K. Takahashi
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures18p.1684 - 16872000年05月-
ISSN:10711023
概要:CdS quantum dots (QDs) were formed on (001) GaAs and ZnSe (ZnSxSe1-x) by the self-assembled method. The nucleation process was monitored by RHEED and no evidence of a wetting layer formation was obtained. Photoluminescence (PL) peak energy shift was also obtained as a function of the volume of CdS deposit. The PL peak energy shift also implied that the wetting layer was not formed.
J. S. Pelt, R. Maga?a, M. E. Ramsey, E. Poindexter, S. Atwell, J. P. Zheng, S. M. Durbin, M. Kobayashi
Materials Research Society Symposium - Proceedings616p.75 - 802000年01月-
ISSN:2729172
概要:There is a great deal of interest in thin film deposition techniques which can achieve good crystal quality at low substrate temperatures. Pulsed laser deposition (PLD), well-known as a reliable technique for fabrication of high critical temperature superconductor thin films, has a number of characteristics which may make it suitable for such applications. In particular, PLD is characterized by a relatively large average species energy, which can be controlled by the laser fluence at the target. This paper describes the growth of silicon on silicon films using PLD over substrate temperatures between 500 and 700 °C, and in-situ characterization using reflection high-energy electron diffraction (RHEED). Transmission electron microscopy confirms the growth of single crystal oriented films, and atomic force microscopy indicates smooth films with an rms surface roughness of less than 2 ?.
A. Jia, T. Furushima, M. Kobayashi, Y. Kato, M. Shimotomai, A. Yoshikawa, K. Takahashi
Journal of Crystal Growth214p.1085 - 10902000年01月-
ISSN:220248
概要:A new candidate for long lifetime short-wavelength light emitters made of hexagonal II-VI compounds has been proposed. In this paper, the results of theoretical design of ZnMgCdOSSe-based light emitters fabricated on (111) plane of GaAs and InP substrates is presented. The band lineups of CdZnS/ZnSSe and CdZnS/ZnMgS structures were estimated with Harrison's LCAO theory. Further, as for the first step of an experimental investigation on the growth of high phase-quality hexagonal II-VI compounds, growth of CdZnS epilayers were examined on GaAs(111) substrate. The epilayers were characterized by high-resolution X-ray diffraction reciprocal space and pole figure measurements. In this study, the optimum growth temperature was 300°C for hexagonal phase CdZnS, and the inclusion of cubic phase CdZnS drastically decreased with increasing Cd content at 300°C.
H Umeya K Kitamura A Jia M Shimotomai Y Kato M Kobayashi A Yoshikawa K Takahashi
J. Cryst. Growth214/215/,192-1962000年00月-
M. Kobayashi
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures17p.2005 - 20081999年12月-
ISSN:10711023
概要:The luminescence properties of self-assembled CdS quantum dots (QDs) were studied. CdS QD structures formed on ZnSe buffer layers without capping layers showed intense photoluminescence (PL). The PL peak position could be controlled by changing the amount of CdS deposited. Introduction of the capping layer enhanced the PL intensity. The buffer layer material selected also affected the luminescence properties of the CdS QDs, and brighter PL with the higher transition energy was observed by replacing the ZnSe buffer layer with ZnSSe. A light emitting diode structure based on CdS QDs sandwiched in the pn junction of ZnSe was fabricated and bright blue or green luminescence from current injection was observed at 77 K as well as at room temperature. ? 1999 American Vacuum Society.
M. ENAMI, K. TSUTSUMI, F. HIROSE, S. KATSUTA and M. KOBAYASHI
Physica Status SolidiVol176 p3971999年11月-
Hailong Zhou, A. V. Nurmikko, M. Kobayashi, A. Yoshikawa
IQEC, International Quantum Electronics Conference Proceedingsp.15 - 161999年01月-
概要:Quantum dots are spectroscopically investigated based on CdS and ZnSe heteroepitaxy by molecular beam methods. The lattice mismatch between CdSe and ZnSe is about 3%, a relative modest value. Another unusual characteristic is that MBE grown CdS layers show a metastable crystallographic feature.
Zhixin Qin, Masakazu Kobayashi, Akihiko Yoshikavva
Journal of Materials Science: Materials in Electronics10p.199 - 2021999年01月-
ISSN:9574522
概要:X-ray diffraction reciprocal space maps and pole figures were used to analyze the cubic GaN epitaxial layers grown on (0 0 1) GaAs by r.f. plasma source MBE; the presence of hexagonal phase in cubic GaN layers was detected by high resolution x-ray analysis and the relationships among various crystal axes of cubic and hexagonal phase GaN were analyzed with respect to V/III source-supply ratio. As for the growth conditions of the epitaxial layers, the V/III ratio was found to drastically affect the quality of the layers. High-temperature growth under near-stoichiometric conditions was necessary to obtain high quality epitaxial layers. It was found that inclusion of the hexagonal phase in the cubic GaN layers could be less than 0.4%, though previously reported typical c-GaN epitaxial layers included as much as 10-20% hexagonal phase GaN. On the basis of the measurements and analyses of reciprocal space maps and pole figures, it was revealed that the orientation of crystal axes of the hexagonal phase was unique in the present GaN epitaxial layers and they were different from those of previously reported c-GaN epitaxial layers.
H. Hayashi, A. Hayashida, A. W. Jia, M. Kobayashi, M. Shimotomai, Y. Kato, A. Yoshikawa, K. Takahashi
Physica Status Solidi (B) Basic Research216p.241 - 2451999年01月-
ISSN:3701972
概要:We found that the direction of the [001] axis of the c-GaN epilayer grown on (001) GaAs was slightly tilted towards the direction of the N-beam during the epitaxial growth by rf-MBE, where the N-beam was incident obliquely to the surface normal. When the tilt of the c-GaN [001] axis was observed, the typical X-ray rocking FWHM value for (002) c-GaN was about 60 arcmin. This indicates that the large mosaicity is related to the tilt of the c-GaN [001] axis. Because the tilt is easily observed for the c-GaN epilayers grown at high growth rate, this implies that the large amount of N species on the growing surface is the origin of the tilt of c-GaN [001] axis. As for the inclusion of the h-GaN phase domain, we found that the peak shifts for the (1011) h-GaN planes occurred in accordance with the peak shift of (002) c-GaN in reciprocal space mappings.
M Kobayashi K Wakao S Nakamura A Jia A Yoshikawa M Shimotomai Y Kato K Takahashi
J. Cryst. Growth201/202/,474-4761999年00月-
A. Yoshikawa, Z. Qin, H. Nagano, Y. Sugure, A. Jia, M. Kobayashi, Y. Kato, K. Takahashi
Materials Science Forum264-268p.1221 - 12241998年12月-
ISSN:2555476
概要:Growth of high-quality and/or "purely cubic" GaN layers on (001) GaAs has been investigated by an rf-radical source MBE paying particular attention to the effect of surface cleaning and smoothing on the structural properties of the GaN epilayers. Device-quality c-GaN layers can be grown on the (001) GaAs treated by atomic hydrogen at high temperatures; the FWHM of X-ray rocking curve for the c-GaN (002) plane is as small as 80-90 arcsec and also the inclusion of the hexagonal phase GaN in the epilayer can be less than 4×10-3.
泰 志新, 賈 岸偉, 小林 正和, 吉川 明彦
真空41(11)p.950 - 9541998年11月-
ISSN:5598516
概要:A two-step atomic-hydrogen (atomic-H) treatment of GaAs substrate was investigated; this includes low-temperature cleaning and high-temperature smoothening of GaAs (001) substrate surface. It was found that atomically flat GaAs surface with one monolayer-height steps and ragged step edges could be obtained by the atomic-H treatment at high temperatures. Further, growth of high quality cubic GaN (c-GaN) on atomic-H treated GaAs (001) was examined by rf plasma-assisted MBE. The c-GaN epilayers were characterized by high resolution X-ray diffraction analysis. The results show that the FWHM of the X-ray rocking curve for the (002) c-GaN was as small as 70-90 arcsec and the inclusion of hexagonal GaN phase was about 0.4% (or below). This indicates that the atomic-H irradiation treatment of the GaAs substrate was an efficient method obtaining High quality c-GaN.
Zhixin Qin, Anwei Jia, Masakazu Kobayashi, Akihiko Yoshikawa
Shinku/Journal of the Vacuum Society of Japan41p.950 - 9541998年11月-
ISSN:5598516
概要:A two-step atomic-hydrogen (atomic-H) treatment of GaAs substrate was investigated; this includes low-temperature cleaning and high-temperature smoothening of GaAs(001) substrate surface. It was found that atomically flat GaAs surface with one monolayer-height steps and ragged step edges could be obtained by the atomic-H treatment at high temperatures. Further, growth of high quality cubic GaN (c-GaN) on atomic-H treated GaAs(001) was examined by rf plasma-assisted MBE. The c-GaN epilayers were characterized by high resolution X-ray diffraction analysis. The results show that the FWHM of the X-ray rocking curve for the (002) c-GaN was as small as 70-90 arcsec and the inclusion of hexagonal GaN phase was about 0.4% (or below). This indicates that the atomic-H irradiation treatment of the GaAs substrate was an efficient method obtaining High quality c-GaN.
Wakao K, Nakamura S, Jia AW, Kobayashi M, Yoshikawa A, Shimotomai M, Kato Y, Takahashi K
JAPANESE JOURNAL OF APPLIED PHYSICS PART 2-LETTERS査読有り37(6B)p.L749 - L7511998年06月-
Z. X. Qin, H. Nagano, Y. Sugure, A. W. Jia, M. Kobayashi, Y. Kato, A. Yoshikawa, K. Takahashi
Journal of Crystal Growth189-190p.425 - 4291998年06月-
ISSN:220248
概要:Cubic GaN epilayers were grown on atomic hydrogen treated (0 0 1)GaAs substrates by RF-radical source molecular beam epitaxy. The crystalline quality was characterized by a high-resolution X-ray diffractometer. It was found that high-quality c-GaN can be grown at temperatures above 680°C; the FWHM of (0 0 2)GaN rocking curve was as small as 80-90 arcsec. In order to further precisely investigate how and to what extent the h-GaN phase is included in the c-GaN layer, the X-ray reciprocal space maps were measured for the X-ray beams incident along both 〈1 1 0〉 and 〈1 1 0〉 azimuths. It was found that the stacking faults exist predominantly on {1 1 1} A planes. The inclusion of h-GaN was estimated by comparing the integrated XRD intensities for h-GaN {1 0 1 1} and c-GaN(0 0 2) planes. It was found that the inclusion of h-GaN phase drastically decreased with increasing growth temperature above 680°C to reach about 4 × 10-3(or below) at temperatures of 710-740°C. ? 1998 Elsevier Science B.V. All rights reserved.
Yoshitaka Taniyasu, Ryouichi Ito, Norio Shimoyama, Megumi Kurihara, Anwei Jia, Yoshinori Kato, Masakazu Kobayashi, Akihiko Yoshikawa, Kiyoshi Takahashi
Journal of Crystal Growth査読有り189-190p.305 - 3091998年06月-
ISSN:220248
概要:Initial growth stages of cubic GaN (c-GaN) films on GaAs(0 0 1) in low-pressure MOVPE were studied by spectroscopic ellipsometry. The GaN buffer layer was deposited at 500°C and was then annealed at 700°C with H2/monomethylhydrazine (MMHy) ambient. Spectroscopic ellipsometry revealed that the buffer layer thickness was increased and the surface was roughened during the annealing process. The change of surface morphology was also confirmed by the atomic force microscopy measurement. These observations would be associated with the nitridation of the GaAs substrate by the ambient MMHy and re-crystallization of the GaN buffer layer. Spectroscopic ellipsometry is a helpful technique to study the initial growth stages of GaN films on GaAs substrates. ? 1998 Elsevier Science B.V. All rights reserved.
Hajime Nagano, Zhixin Qin, Anwei Jia, Yoshinori Kato, Masakazu Kobayashi, Akihiko Yoshikawa, Kiyoshi Takahashi
Journal of Crystal Growth189-190p.265 - 2691998年06月-
ISSN:220248
概要:Substrate surface treatment techniques and growth conditions are the key of growing high-quality cubic GaN (c-GaN) epitaxial layers on (0 0 1) GaAs substrates. An atomically flat (0 0 1) GaAs substrate surface can be obtained by a two-step atomic hydrogen (atomic-H) irradiation technique. The typical surface of the substrate treated by the atomic-H consists of narrow terraces of one monolayer step height with acute-angle polygonal structures. The X-ray rocking curve FWHM of GaN (0 0 2) grown on the atomic-H treated substrate is less than 90 arcsec. It is shown that high-density monolayer steps and kinks at the surface terrace edge would be preferable for the uniform nucleation of the c-GaN buffer layer. ? 1998 Elsevier Science B.V. All rights reserved.
M. Kobayashi, S. Nakamura, K. Wakao, A. Yoshikawa, K. Takahashi
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures16p.1316 - 13201998年05月-
ISSN:10711023
概要:CdS quantum dot (QD) structures were grown by molecular beam epitaxy on (001) ZnSe. Circular QDs were observed from the sample grown at 220 °C, whereas rectangular QDs were observed from the sample grown at 280 °C. The difference of the dot shape may be related to the metastable nature of CdS since CdS thin films grown at 220 °C show zincblende structures and thin films grown at 280 °C show wurtzite structures. The PL peak position and linewidth were strongly affected by the growth condition of QDs; QD samples with a thicker CdS deposition showed redshifts of the peak position along with the narrowing of the linewidth. ? 1998 American Vacuum Society.
M. Kobayashi, C. Setiagung, K. Wakao, S. Nakamura, A. Yoshikawa, K. Takahashi
Journal of Crystal Growth184-185p.66 - 691998年01月-
ISSN:220248
概要:ZnS1-xTexand Zn1-yMgyS1-xTexepilayers were grown on (1 0 0)GaAs by MBE. Ternary and quaternary alloys can be lattice matched to GaAs by adjusting the composition of the group VI and group II elements. Zincblende structure layers were grown and p-doping was achieved. A fairly good ohmic contact profile was obtained between gold and the alloy. By using the Au/p-ZnS1-xTexcontacting layer, ohmic contact was obtained to p-ZnSe. p-Zn1-yMgyS1-xTexlayers were applied to cladding layers of the LED, and bright luminescence was observed. ? 1998 Elsevier Science B. V. All rights reserved.
A. Yoshikawa, H. Nagano, Z. X. Qin, Y. Sugure, A. W. Jia, M. Kobayashi, M. Shimotomai, Y. Kato, K. Takahashi
Materials Research Society Symposium - Proceedings482p.227 - 2321997年12月-
ISSN:2729172
概要:Growth of high quality c-GaN on atomic-H treated (001) GaAs was examined by rf plasma-assisted MBE. First the initial growth stages (atomic-H treatment of GaAs, nitridation/deposition of a thin GaN buffer layer, the post deposition annealing of the buffer layer, and epitaxy of c-GaN) were studied by RHEED and AFM observations. It was found that atomically flat GaAs surface with one monolayer-height steps and ragged step edges could be obtained by the atomic-H treatment at high temperatures. It was found that the atomic-H treated GaAs surface was preferable to grow high quality c-GaN; the FWHM of the X-ray rocking curve for the (002) c-GaN was as small as 70-90 arcsec.
A. Yoshikawa, Z. X. Qin, H. Nagano, Y. Sugure, A. W. Jia, M. Kobayashi, M. Shimotomai, Y. Kato, K. Takahashi
Materials Research Society Symposium - Proceedings482p.465 - 4701997年12月-
ISSN:2729172
概要:Cubic GaN (c-GaN) layers were grown by rf-plasma source MBE on (001) GaAs prepared by atomic-hydrogen treatment at `high temperatures', and the structural properties of the epilayers were investigated by the high-resolution X-ray rocking curve and the reciprocal space mapping measurements. The growth temperature was varied from 620 to 740 °C. It was found that single domain `device-quality' c-GaN layers could be grown for the first time; the FWHM of the X-ray rocking curves for the (002) c-GaN could be as small as 70-90 arcsec and the inclusion of h-GaN phase in the c-GaN epilayers grown at temperatures above 680 °C could be less than 4×103.
Kengou Yamaguchi, Kengou Yamaguchi, Zhixin Qin, Hajime Nagano, Masakazu Kobayashi, Akihiko Yoshikawa, Kiyoshi Takahashi
Japanese Journal of Applied Physics, Part 2: Letters361997年10月-
ISSN:214922
概要:An atomically flat GaAs(001) surface can be obtained by a two-step atomic hydrogen (atomic-H) irradiation technique. This method includes low-temperature cleaning and high-temperature smoothening of the GaAs subtle surface. The reflection high energy electron diffraction (RHEED) and AFM study showed that a wide terrace with a 1 monolayer step height was observed when a GaAs(001) surface was cleaned at 400°C and smoothened at 540°C with atomic-H irradiation. The irradiation of atomic-H during the high temperature process maintained a certain surface stoichiometry, and resulted in an atomically flat substrate surface. This technique is useful for heterovalent epitaxy systems involving a single chamber growth system.
永野 元, 秦 志新, 賈 岸偉, 加藤 嘉則, 小林 正和, 吉川 明彦
電子情報通信学会技術研究報告. LQE, レーザ・量子エレクトロニクス97(100)p.37 - 421997年06月-
概要:六方晶構造が安定であるGaN(h-GaN)をGaAs(001)や3C-SiC(001)等の立方晶構造の基板上に成長することで, 立方晶構造のGaN (c-GaN)を作製できる. c-GaNはLDデバイス化に際し共振器や電極の形成がh-GaNに比べて容易であると考えられている. しかし基板表面や成長表面に凹凸が存在すると, c-GaN中には元々安定であるh-GaNが混在しやすく高品質なc-GaNを得るのが難しい. そこで, 本研究では原子状水素(H^*)を用いて清浄化及び平坦化を行ったGaAs基板上に, rf-MBE法によりGaNの成長を行った. その結果, GaN(002)X線ロッキングカープにおいてFWHMが90arcsecであるような, 高品質のc-GaNを得ることができた. これは, H^*により処理したGaAs基板表面が, 分子層オーダーで平坦でありそのステップ端に多数のキンクを持つため, 成長初期において成長核が一様, 高密度に生成し, GaNが一様に成長したためと考えられる.
Gunshor Robert L., Nurmikko Arto V., 小林 正和
日経サイエンス26(9)p.34 - 381996年09月-
ISSN:0917009X
T. Yamada, C. Setiagung, A. W. Jia, M. Kobayashi, A. Yoshikawa
Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures14p.2371 - 23731996年05月-
ISSN:10711023
概要:The metastable nature of molecular-beam epitaxy grown CdS layers was studied. Undoped CdS layers were grown on (100) GaAs substrates/(100) ZnSe buffer layers, and crystal structures were characterized by x-ray diffraction and transmission electron microscopy. Undoped films showed both zincblende and wurtzite structures depending on the growth condition; higher substrate temperatures and smaller VI/II beam intensity ratios preferentially form wurtzite structures. The Ga doping significantly affected the crystal structure and Ga doped CdS layers preferentially formed wurtzite structures. Thermal instability of the CdS film was observed through various ex situ annealing experiments. The wurtzite structure phase was developed from the zincblende structure CdS layers by thermal annealing where the annealing temperature was lower than the growth temperature. ? 1996 American Vacuum Society.
T. Yoshida, T. Nagatake, M. Kobayashi, A. Yoshikawa
Journal of Electronic Materials25p.195 - 1991996年01月-
ISSN:3615235
概要:Interfacial layers were inserted at the interface of ZnSe and ZnTe in order to reduce both (1) the effect of strain and (2) the valence band discontinuity. The interfacial layer adapted in this study is the III-VI compound (Ga,Se). The layered structure GaSe is favorable for the present work, because it can be a buffer layer to relax the lattice mismatch at the interface. All layers including ZnTe, (Ga,Se) and ZnSe were grown on (100) GaAs substrate by conventional molecular beam epitaxy. The crystal structure of the (Ga,Se) on ZnSe was investigated. The growth of the layered structure GaSe layer on (100) ZnSe was very difficult, though the defect zinc-blende structure Ga2Se3layer could be easily grown. The defect zinc-blende structure Ga2Se3was inserted at the interface of ZnSe and ZnTe so that the valence band discontinuity could be modified. The discontinuity was decreased to about 0.1 eV when the thickness of the interfacial layer was about 8?. The current-voltage characteristics were measured for the sample with Ga2Se3interfacial layer. The structure with Ga2Se3exhibited the ohmic property. These results suggest that the valence band discontinuity between ZnTe and ZnSe can be reduced by introducing the Ga2Se3interfacial layer.
M. Miyachi, Y. Ohira, S. Komatsu, M. Kurihara, N. Shimoyama, M. Kobayashi, Y. Kato, A. Yoshikawa
Journal of Crystal Growth159p.261 - 2651996年01月-
ISSN:220248
概要:Growth and p-type doping processes in MOVPE of ZnSe have been studied by optical probing methods called RD (reflectance difference) and SPI (surface photo-interference). As for the dopant source, tertiarybutyl-amine (tBNH2) was extensively used in this work, because it is one of the most useful dopant sources in photo-assisted MOVPE of widegap II-VI compounds. Oscillations with monolayer periodicity in RD signal traces have been successfully detected for the first time using a He-Ne laser beam in MOVPE of ZnSe. One of the most important findings is that tBNH2molecules are selectively adsorbed on the "Zn-terminated" surface and not on the "Se-terminated" surface; this suggests that selective doping during Zn-source (DMZn) supply and/or on Zn-terminated surfaces will be effective for improving the doping efficiency.
T. Yoshida, T. Nagatake, M. Kobayashi, A. Yoshikawa
Journal of Crystal Growth159p.750 - 7531996年01月-
ISSN:220248
概要:The defect zincblende structure Ga2Se3was inserted at the interface of ZnSe and ZnTe so that the valence band discontinuity (ΔEv) could be modified. The valence band discontinuity was determined from the capacitance-voltage (C-V) measurement technique. The measured ΔEvdepended on the thickness of the Ga2Se3interfacial layer. The discontinuity became negligible when the thickness of the interfacial layer was about 4 ?. The current-voltage (I-V) characteristics for the Au/p-ZnTe/Ga2Se3/p-ZnSe/p-GaAs structure exhibited a perfectly linear plot when the thickness of the interfacial layer was about 8 ?. These results suggest that the valence band discontinuity between ZnTe and ZnSe can be reduced by introducing the Ga2Se3interfacial layer.
Yoshida T, Kobayashi M, Yoshikawa A
BLUE LASER AND LIGHT EMITTING DIODES査読有りp.461 - 4641996年00月-
R. J. Thomas, Benjamin Rockwell, H. R. Chandrasekhar, Meera Chandrasekhar, A. K. Ramdas, M. Kobayashi, R. L. Gunshor
Journal of Applied Physics78p.6569 - 65731995年12月-
ISSN:218979
概要:A study of biaxial strain as a function of temperature in a ZnSe epilayer grown on a GaAs substrate is presented. The strains are determined by measuring the heavy- and light-hole related excitonic transitions via photomodulated spectroscopy. The strain is found to increase with increasing temperature. The data are compared with a calculation using a previously determined elastic constant and thermal expansion coefficients. The temperature dependence determined here allows a comparison of various other optical measurements performed at different temperatures. ? 1995 American Institute of Physics.
Y. Nakamura, T. Yamashita, M. Kobayashi, Y. Kato, A. Yoshikawa
Proceedings of the IEEE/CPMT International Electronic Manufacturing Technology (IEMT) Symposiump.387 - 3901995年12月-
概要:A new in-situ optical probing method with an atomic-scale resolution in thin film deposition and/or heteroepitaxial growth is proposed in this paper. The new method is named surface photo-interference (SPI) because it is essentially concerned with a photo-interference in the deposited layer. The principle of the SPI is as follows; the complex refractive indices of the atomic or molecular layers, which alternately appear on top of the surface during film deposition and/or heteroepitaxy, greatly affect the total phase-shift of probing light during propagation in the epilayer, resulting in the change in the photo-interference signal intensity. The experimental setup of the method is very similar to that for another optical probing method called surface photo-absorption (SPA), but the principle is quite different between those two. One of the features of the SPI is that the experimental setup is quite simple and inexpensive though it is quite useful in real time monitoring of the thin film deposition.
A. W. Jia, M. Kobayashi, A. Yoshikawa
Journal of Electronic Materials査読有り24(3)p.117 - 1211995年03月-
ISSN:3615235
概要:Theoretical design of pseudo-ternary and quaternary alloys by superlattice structures consisting of (Zn,Cd)(S,Se) binary II-VI compounds has been studied. For pseudo-ternary ZnCdS and ZnCdSe alloys, the superlattices with two layers in a cycle, i.e., ZnS/CdS and ZnSe/CdSe are considered, and for pseudo-quaternary ZnCdSSe alloy, the two superlattice structures with more than two layers in a cycle are considered. In order to design and evaluate these superlattices, the expression for the equilibrium in-plane lattice constant of these superlattices has been derived by minimizing the total elastic strain energy in the cycle. The combinations of layer thicknesses in a cycle and the effective bandgap of these superlattices have been calculated while the elastic strain effect was included. The usefulness of these superlattice structures has been evaluated. ? 1995 The Metallurgical of Society of AIME.
Wataru Imajuku, Masashi Takahashi, Masakazu Kobayash, Akihiko Yoshikawa
Japanese Journal of Applied Physics34p.1861 - 18661995年01月-
ISSN:214922
概要:Theoretical design of ZnSSe/ZnCdSSe laser diodes emitting 460 nm at room temperature (RT) was studied by means of threshold current analysis. The threshold current density calculation was based on the laser theoryestablished for the III-V laser diode (LD) system. The result of the threshold current density calculation indicatedthat the reduction of carrier overflow is an essential issue in realizing the device with a reasonable threshold currentlevel at RT. Another indication is that 30% S content in the ZnSSe cladding layer would be a suitable targetvalue for a practical 460 nm LD at RT, along with a multiple quantum barrier structure. The predicted thresholdcurrent density of such a LD could be as low as 450 A/cm2 at RT. ? 1995 The Japan Society of Applied Physics.
A. W. Jia, T. Yamada, M. Kobayashi, A. Yoshikawa
Materials Science Forum182-184p.403 - 4061995年01月-
ISSN:2555476
概要:We report on the molecular beam epitaxial (MBE) growth of sulfur-based binary and ternary widegap II-VI alloys using elemental sulfur source. The growth temperatures used arranged from 180 to 310°C. The valved-cracker cell with three independently controllable heaters is used for the S source. The epitaxial layers were grown using thermally cracked S source at 200, 500 and 900°C, and the film quality was characterized by X-ray diffraction and photoluminescence.
A. Yoshikawa, M. Kobayashi, S. Tokita
physica status solidi (b)187p.315 - 3251995年01月-
ISSN:3701972
概要:The surface reaction mechanism in MOMBE‐ALE of ZnSe and CdSe using DMZn, DMCd, and H2Se as reactants is studied with a newly developed optical in‐situ monitoring method. The new method is named surface photo‐interference (SPI), because the concept of the SPI is essentially concerned with a photo‐interference in the heteroepilayer. Fairly low‐energy photons for which the epilayer is transparent can be used as probing light in SPI. Reflecting this feature, SPI is especially useful for studying heteroepitaxial growth kinetics of wide‐gap II‐VI compounds, because the effect of photocatalytic growth rate enhancement can be avoided when using such low energy photons as probing light. It is shown that there is a quite significant difference in the surface reaction mechanism between the MOMBE‐ALE of ZnSe and CdSe. That is, in the ALE of ZnSe when none of the source gases are per‐cracked, the reaction to form ZnSe can take place when the group‐II source (i.e., DMZn) is supplied, resulting in an alternate appearance of Zn terminated and H2Se terminated surfaces during growth. On the other hand, the reaction to form CdSe can do when the group‐VI source (i.e., H2Se) is supplied, resulting in an alternate appearance of Se terminated and DMCd terminated surfaces during growth. Copyright ? 1995 WILEY‐VCH Verlag GmbH & Co. KGaA
Akihiko Yoshikawa, Masakazu Kobayashi, Shigeru Tokita
Applied Surface Science82-83p.316 - 3211994年12月-
ISSN:1694332
概要:The surface reaction mechanism in MOMBE-ALE of ZnSe and CdSe using DMZn, DMCd and H2Se as reactants has been studied with a newly developed optical in-situ monitoring method named surface photo-interference (SPI). It is shown that there is a quite significant difference in the surface reaction mechanism between the MOMBE-ALE of ZnSe and CdSe. That is, in the ALE of ZnSe when none of the source gases are pre-cracked, the reaction to form ZnSe can take place when the group-II source (i.e., DMZn) is supplied, resulting in an alternate appearance of Zn-terminated and H2Se-terminated surfaces during growth. On the other hand, the reaction to form CdSe can take place when a group-VI source (i.e., H2Se) is supplied, resulting in an alternate appearance of Se-terminated and DMCd-terminated surfaces during growth. ? 1994.
Akihiko Yoshikawa, Masakazu Kobayashi, Shigeru Tokita
Journal of Crystal Growth145p.68 - 731994年12月-
ISSN:220248
概要:A new in-situ optical probing method for studying surface reactions during heteroepitaxial growth is proposed. The new method is named surface photo-interference (SPI), because the concept of the SPI is essentially concerned with a photo-interference in the heteroepilayer. The experimental setup of the method is very similar to another optical probing method called surface photo-absorption (SPA), but the principle is quite different between the two. Unlike SPA, fairly low energy photons that are transparent for the epilayer can also be used in SPI as a probing light. Reflecting this feature, SPI is especially useful for studying growth kinetics in heteroepitaxial growth of widegap II-VI compounds, because the effect of photocatalytic growth-rate enhancement can be avoided when using such low energy photons as a probing light. A brief theoretical description of SPI signal is given, and experimental results detected in metalorganic molecular beam energy (MOMBE) of ZnSe and CdSe are mainly discussed. Further, how SPI differs from SPA will be shown. ? 1994.
Masakazu Kobayashi, Akihiko Yoshikawa
Materials Research Society Symposium - Proceedings340p.437 - 4451994年12月-
ISSN:2729172
概要:Nitrogen and helium mixed gas plasma was used to grow p-ZnSe. Using the mixed gas, the acceptor concentration could be controlled from 6×1016 to 7×1017 cm-3 while films doped using the nitrogen plasma exhibited the acceptor concentration of 3×1017 cm-3. Doping characteristics such as the acceptor concentration and the PL properties depend on the gas mixing ratio and the rf power. Plasma spectroscopy was used to characterize the variety of the species in the plasma. Although the variety of the nitrogen related peaks in the spectrum were not significantly affected by the gas mixing, several peaks (for example 745nm and 825nm) showed intensity variation that was similar to the acceptor concentration variation with respect to the N2 and He gas mixing ratio.
Akihiko Yoshikawa, Msasakazu Kobayashi, S. Tokita
Applied Surface Science79-80p.416 - 4211994年05月-
ISSN:1694332
概要:A new in-situ optical probing method with an atomic-scale resolution in heteroepitaxial growth is proposed. The experimental set-up of the method is very similar to another optical probing method called surface photo-absorption (SPA), but the principle is quite different. The new method is named surface photo-interference (SPI) because it is essentially concerned with photo-interference in the heteroepilayer. The principle of the SPI is as follows: the complex refractive indices of the atomic or molecular layers, which alternately appear on top of the surface during epitaxial growth of compound semiconductors, greatly affect the total phase shift of probing light during propagation in the epilayer, resulting in a change in the photo-interference signal intensity. One of the features of the SPI is that, unlike in the case of SPA, fairly low energy photons which are transparent for the epilayer can also be used as probing light. This is very preferable for studying the growth kinetics and/ or surface reaction in photo-excited epitaxial growth of widegap II-VI compounds, because the effect of photocatalytic growth-rate enhancement can be avoided when using such low energy photons as probing light. ? 1994.
M. Kobayashi, H. Tosaka, T. Nagatake, T. Yoshida, A. Yoshikawa
Journal of Crystal Growth138p.745 - 7491994年04月-
ISSN:220248
概要:Nitrogen and helium mixed gas plasma was used to control the acceptor concentration of p-ZnSe and p-ZnSSe. Using the mixed gas, the acceptor concentration of p-ZnSe can be controlled from 6 × 1016to 7 × 1017cm-3, whereas the acceptor concentration of p-ZnSSe can be controlled from 4 × 1016to 4 × 1017cm-3. Doping characteristics such as the acceptor concentration and the PL properties depend on the gas mixing ratio and the RF power. p-Layers grown with this technique were used for blue-green laser diode structures. Lasing was observed at 77 K under pulsed operation. ? 1994.
S. Tokita, M. Kobayashi, A. Yoshikawa
Journal of Crystal Growth136p.376 - 3801994年03月-
ISSN:220248
概要:The metalorganic molecular beam epitaxy (MOMBE) growth process of ZnSe on GaAs was characterized by the surface photo-interference (SPI) method. The SPI signal traces were monitored in various experiments where the source gas cracking conditions were varied. The signal features, such as intensity and polarity, were drastically modified by the Se source gas cracking, whereas the signal was hardly affected by the Zn source gas cracking. Zn-terminated surfaces formed by uncracked dimethylzinc (DMZn) gas supply as well as the cracked gas supply are likely to be covered with Zn atoms. On the other hand, the Se-terminated surface formed by the uncracked H2Se gas supply is probably covered with H2Se molecules. ? 1994.
Robert J. Thomas, Mark S. Boley, H. R. Chandrasekhar, Meera Chandrasekhar, C. Parks, A. K. Ramdas, J. Han, M. Kobayashi, R. L. Gunshor
Physical Review B49p.2181 - 21841994年01月-
ISSN:1631829
概要:The piezomodulated-, electromodulated-, and photomodulated-reflectivity spectra of a pseudomorphic ZnTe epilayer, grown on an InAs epilayer by molecular-beam epitaxy, exhibit heavy- and light-hole excitonic signatures split by the lattice mismatch induced biaxial compressive strain. This splitting in the pseudomorphic epilayer is studied as a function of applied hydrostatic pressure using photomodulated reflectance spectroscopy at 80 K. With increasing hydrostatic compression, the compressive strain is progressively compensated by the pressure-induced tensile strain. At ?55 kbars the epilayer becomes strain-free, and is under a biaxial tension at higher pressures. The separation between the heavy- and light-hole signatures is superlinear in pressure, suggestive of a strain or volume deformation-dependent shear deformation-potential constant. We also compare the pressure dependence of the Raman LO phonon of the ZnTe epilayer on InAs with that of a bulk ZnTe sample at 13 K. The pressure-dependent strain is found to be linear. Accurate values of the first-order strain derivatives of the LO phonons and mode Gr?neisen constants are obtained. ? 1994 The American Physical Society.
賈 岸偉, 小林 正和, 吉川 明彦
電気学会論文誌E(センサ・マイクロマシン部門誌)114(12)p.1286 - 12911994年00月-
ISSN:0385-4221
概要:In this paper, we propose two superlattice structures as pseudo-quaternary ZnCdSSe layers. They consist of three layers or four layers in a cycle with three kinds of binary compound materials, i.e., ZnS, ZnSe and CdS. In order to estimate the equilibrium in-plane lattice constant of these layers, a general expression for superlattices consisting of n (n=2, 3, 4, …) layers in a cycle has been derived by minimizing the total elastic strain energy. The effective bandgap for the superlattices with different combinations of the layer thickness in a cycle were calculated using Kronig-Penney model, where the strain effect was taken into account in calculating the bandgap and the band offset. The calculated results of the effective bandgaps were compared with the bandgap of ZnCdSSe quaternary alloy.
Mark S. Boley, Robert J. Thomas, Meera Chandrasekhar, H. R. Chandrasekhar, A. K. Ramdas, M. Kobayashi, R. L. Gunshor
Journal of Applied Physics査読有り74p.4136 - 41441993年12月-
ISSN:218979
概要:The heavy-hole and light-hole excitons of a CdTe epilayer, pseudomorphically grown on an InSb epilayer by molecular beam epitaxy, are studied with a diamond anvil cell as a function of applied hydrostatic pressure via photoluminescence (PL) and photomodulated reflectivity (PR) spectroscopies. They are compared with the excitonic features in the simultaneously measured PL spectra of a sample of bulk CdTe. Under applied pressure, the lattice mismatch-induced splitting between the light-hole and heavy-hole related transitions increases in a continuous and reversible manner because of the additional pressure-induced compression due to the difference in the compressibilities of CdTe and InSb. The unusually large strain sustained by the CdTe epilayer under pressure is discussed in the light of various models. The PR signal vanishes after the InSb epilayer goes through a structural phase transition at approximately 20 kbar, while the PL signal persists until it is irreversibly quenched by the CdTe epilayer undergoing a structural phase transition at approximately 30 kbar. For pressures between 20 and 30 kbar, the behavior of the CdTe epilayer is similar to that of the bulk sample; the strain appears to have been relaxed due to the structural phase transition which has taken place in InSb. Values of the first- and second-order pressure coefficients for bulk CdTe and for the CdTe epilayer as well as values of the hydrostatic and shear deformation potentials are obtained at 14 and 80 K and compared with previously quoted values.
J. Han, T. S. Stavrinides, M. Kobayashi, R. L. Gunshor, M. M. Hagerott, A. V. Nurmikko
Applied Physics Letters62p.840 - 8421993年12月-
ISSN:36951
概要:The successful p-doping of ZnSe and Zn(S,Se) using a nitrogen plasma source during growth by molecular beam epitaxy has been an important factor leading to the recent realization of blue-green diode lasers and light-emitting diodes. This letter reports the results of the nitrogen doping of ZnTe using similar techniques. Doping levels approaching the 1019cm-3range are reported along with electrical, optical, and microstructural characterization. Highly doped ZnTe provides an opportunity for forming an ohmic contact to p-ZnSe.
J. Han, T. S. Stavrinides, M. Kobayashi, R. L. Gunshor, M. M. Hagerott, A. V. Nurmikko
Journal of Electronic Materials22p.485 - 4881993年05月-
ISSN:3615235
概要:In recent months the successful p-doping of ZnSe and Zn(S,Se) using a nitrogen plasma source during growth by molecular beam epitaxy was one factor leading to the realization of diode lasers and light emitting diodes. This paper reports the results of the nitrogen doping of ZnTe using similar techniques. Doping levels exceeding the 1019cm-3range are reported along with electrical, optical, and microstructural characterization. The nitrogen-doped ZnTe is used to implement p-ZnTe/n-AISb diodes; the growth and characterization of these hetero-junction diodes are described. ? 1993 The Mineral,Metal & Materials Society,Inc.
D. C. Grillo, W. Xie, M. Kobayashi, R. L. Gunshor, G. C. Hua, N. Otsuka, H. Jeon, J. Ding, A. V. Nurmikko
Journal of Electronic Materials22p.441 - 4441993年05月-
ISSN:3615235
概要:The use of a nitrogen radio frequency plasma source together with an appropriate quantum well configuration have recently resulted in the successful realization of p-type ZnSe by molecular beam epitaxy. This has enabled a variety of pn heterojunction based devices to be built including the first semiconductor injection lasers operating in the blue/green portion of the spectrum first reported by 3M and the Brown/Purdue group. In this paper, we discuss two lattice matched multiple quantum well structures that produce laser emission in the blue and blue/green portion of the spectrum. ? 1993 The Mineral,Metal & Materials Society,Inc.
W. Xie, D. C. Grillo, M. Kobayashi, L. He, R. L. Gunshor, H. Jeon, J. Ding, A. V. Nurmikko, G. C. Hua, N. Otsuka
Journal of Crystal Growth127p.287 - 2901993年02月-
ISSN:220248
概要:We describe the performance of pn junction MQW diode lasers and LEDs which are grown on both p-type and n-type GaAs substrates. Efforts to minimize dislocations by lattice matching the II-VI region to the GaAs substrate in some cases resulted in obtaining dislocation densities below 105cm-2. We have obtained pulsed high power, high quantum efficiency laser emission up to room temperature conditions, and continuous operation at liquid nitrogen temperatures. Efficient LED and display devices operate in the blue (490-494 nm) at room temperature. ? 1993.
H. Jeon, D. C. Grillo, W. Xie, M. Hagerott, J. Ding, M. Kobayashi, R. L. Gunshor, A. V. Nurmikko
Optics Letters18p.125 - 1271993年01月-
ISSN:1469592
概要:Low-threshold current density operation has been obtained from (Zn, Cd)Se/Zn(S, Se) quantum-well diode lasers in the blue-green spectrum. The devices, with reflective facet coatings, have been operated at room temperature under pulsed conditions with threshold current densities of Ith? 1 kA/cm2. ? 1993 Optical Society of America.
Shigeyuki Matsumoto, Hiroyuki Tosaka, Takashi Yoshida, Masakazu Kobayashi, Akihiko Yoshikawa
Japanese Journal of Applied Physics32p.731 - 7351993年01月-
ISSN:214922
概要:Two methods were examined for doping nitrogen into ZnSe and ZnCdSe. N2gas was thermally excited in the first method. The photoluminescence (PL) spectra showed that acceptor levels were formed in the film; this feature was similar to that observed in the samples doped with nonexcited N2gas. The second method utilized pho-toexcited N2O and N2gases using vacuum ultraviolet (VUV) light. A deuterium lamp was used for the VUV-light source. Deep-emission-dominant PL spectra were observed when films were doped using photoexcited N2O gas. N2O gas was then mixed with N2gas to control the photodecomposition process and improve the film quality. Samples doped using the mixed gas exhibited well-resolved near-band-edge features. The PL spectrum of the ZnO.9 Cdo.iSe sample doped using the photoexcited mixed gas showed donor-acceptor pair emission. ? 1993 The Japan Society of Applied Physics.
Shigeyuki Matsumoto, Hiroyuki Tosaka, Takashi Yoshida, Takashi Yoshida, Masakazu Kobayashi, Akihiko Yoshikawa
Japanese Journal of Applied Physics321993年01月-
ISSN:214922
概要:Planar doping of nitrogen into ZnSe is examined. The dependence of doping efficiency on the particular surface termination (Zn- or Se-stabilised) on (100) ZnSe is investigated through capacitance-voltage measurement and low-temperature photoluminescence (PL) spectroscopy. Using planar doping on the Zn surface, we achieved a hole concentration of 4.5 x 1017 cm-3, and the PL spectrum is dominated by strong donor-acceptor pair (DAP) emissions. By contrast, the film planar-doped on the Se plane shows rather low hole concentration, and the spectrum is dominated by excitonic features along with very weak DAP emissions. ? 1993 The Japan Society of Applied Physics.
Hiroyuki Tosaka, Tsuyoshi Nagatake, Takashi Yoshida, Masakazu Kobayashi, Akihiko Yoshikawa
Japanese Journal of Applied Physics321993年01月-
ISSN:214922
概要:Nitrogen and helium mixed gas plasma was used to grow p-ZnSe. Using the mixed gas, the acceptor concentration can be controlled from 6 x 1016to 7 x 1017cm-3while films doped using the nitrogen plasma exhibited the acceptor concentration of 3 x 1017cm-3. Doping characteristics such as the acceptor concentration and the PL properties depend on the gas mixing ratio and the rf power. p-ZnSe layers grown with this technique were used for blue-green laser structures. Lasing was observed at 77 K under pulse operation. ? 1993 The Japan Society of Applied Physics.
M. S. Boley, R. J. Thomas, M. Chandrasekhar, H. R. Chandrasekhar, A. K. Ramdas, M. Kobayashi, R. L. Gunshor
Journal of Applied Physics査読有り74p.4136 - 41441993年00月-
W. Xie, D. C. Grillo, R. L. Gunshor, M. Kobayashi, G. C. Hua, N. Otsuka, H. Jeon, J. Ding, A. V. Nurmikko
Applied Physics Letters60p.463 - 4651992年12月-
ISSN:36951
概要:The successful p doping of ZnSe by substitutional nitrogen using a plasma cell incorporated into the molecular beam epitaxy chamber has led to the development of electroluminescent devices based on carrier injection at a pn junction. The light emitting diode structures described here are grown on a GaAs substrate using a tetragonally distorted (In,Ga)As buffer layer to provide lattice matching between the substrate and the active II-VI region. The result of the incorporation of the buffer layer is an essentially dislocation-free active region. The letter discusses optical properties as well as the x-ray and transmission electron microscopy characterization of the quantum well device structures.
H. Jeon, J. Ding, A. V. Nurmikko, W. Xie, D. C. Grillo, M. Kobayashi, R. L. Gunshor, G. C. Hua, N. Otsuka
Applied Physics Letters60p.2045 - 20471992年12月-
ISSN:36951
概要:Laser diode operation has been obtained from (Zn,Cd)Se/ZnSe and (Zn,Cd)Se/Zn(S,Se) quantum well structures in the blue and the green. The devices, prepared on p- and n-type (In,Ga)As or GaAs buffer layers for lattice matching purposes to control the defect density, have been operated at near-room-temperature conditions and briefly at room temperature with uncoated end facets. Quasi-continuous wave operation has been obtained at T=77 K.
H. Jeon, J. Ding, A. V. Nurmikko, W. Xie, M. Kobayashi, R. L. Gunshor
Applied Physics Letters60p.892 - 8941992年12月-
ISSN:36951
概要:pn junction characteristics and LED action in ZnSe-based multilayers grown by molecular beam epitaxy is demonstrated. In particular, we show that (Zn,Cd)Se/ZnSe/Zn(S,Se) structures containing (Zn,Cd)Se quantum wells, grown on p-type GaAs epilayers, and designed with a heavily doped n+-ZnSe top contact layer may be appropriate for display device applications in the blue-green portion of the spectrum.
M. Hagerott, H. Jeon, A. V. Nurmikko, W. Xie, D. C. Grillo, M. Kobayashi, R. L. Gunshor
Applied Physics Letters60p.2825 - 28271992年12月-
ISSN:36951
概要:Sputter deposited indium tin oxide layers have been used as the top contact for blue LEDs and diode lasers in (Zn,Cd)Se/Zn(S,Se) quantum well heterostructures. The contact resistance to n-Zn(S,Se) is comparable to that with indium or gold. The optically transparent contacts have been utilized, as an example, in the fabrication of a numeric display device and to show that LED emission is of excitonic origin in these type I quantum wells.
W. Xie, D. C. Grillo, R. L. Gunshor, M. Kobayashi, H. Jeon, J. Ding, A. V. Nurmikko, G. C. Hua, N. Otsuka
Applied Physics Letters60p.1999 - 20011992年12月-
ISSN:36951
概要:Blue (494 nm) light emitting quantum well diodes based on Zn(S,Se) p-n junctions are demonstrated at room temperature. P-type Zn(S,Se) is realized by using a nitrogen rf plasma cell. The light emitting diode is formed on homoepitaxial GaAs buffer layers by molecular beam epitaxy. The S fraction of the alloy is selected to provide a lattice match between the II-VI active region and the GaAs buffer; the result is an active region having a dislocation density below 105/cm-2. The letter discusses emission characteristics as well as the x-ray rocking curve and transmission electron microscopy characterization of the structures.
Masakazu Kobayashi, Robert L. Gunshor, Arto V. Nurmikko, Nobuo Otsuka
Optoelectronics Tokyo7p.1 - 101992年06月-
ISSN:9125434
概要:The successful p-doping of ZnSe by substitutional nitrogen using a plasma cell incorporated into a molecular beam epitaxy chamber has led to the development of electroluminescent devices employing carrier injection at a p-n junction and in which the active region is based on (Zn,Cd) Se/Zn(S,Se) multiple quantum well structures. We report on the performance of p-n junction MQW diode lasers and LEDs which are grown on both p-type and n-type GaAs substrates, and where sulfur is, or is not incorporated. For all structures, efforts were made to minimize dislocations by lattice matching the active II-VI region to the GaAs substrate. Some designs have dislocation densities below 105 cm-2. In this work we have obtained pulsed high power, high quantum efficiency laser emission up to room temperature conditions, and continuous operation at liquid nitrogen temperatures. Efficient LED devices are described which operate in the blue (494 nm) at room temperature.
XIE W, GRILLO DC, GUNSHOR RL, KOBAYASHI M, HUA GC, OTSUKA N, JEON H, DING J, NURMIKKO AV
JOURNAL OF VACUUM SCIENCE & TECHNOLOGY B査読有り10(2)p.921 - 9231992年03月-
ISSN:1071-1023
W. Xie, D. C. Grillo, M. Kobayashi, R. L. Gunshor, G. C. Hua, N. Otsuka, H. Jeon, J. Ding, A. V. Nurmikko
Journal of Crystal Growth117p.10791992年02月-
ISSN:220248
A. V. Nurmikko, R. L. Gunshor, M. Kobayashi
Journal of Crystal Growth117p.432 - 4401992年02月-
ISSN:220248
概要:The optical properties of (Zn,Cd)Se/ZnSe quantum wells are reviewed with emphasis on recent results on quasi-two-dimensional excitons, light emitting diodes, as well as on optically pumped lasers and diode lasers in this type I system. ? 1992.
H. Jeon, M. Hagerott, J. Ding, A. V. Nurmikko, W. Xie, D. C. Grillo, M. Kobayashi, R. L. Gunshor, G. C. Hua, N. Otsuka
IEEE Transactions on Electron Devices39p.2652 - 26531992年01月-
ISSN:189383
D. Li, Y. Nakamura, N. Otsuka, J. Qiu, M. Kobayashi, R. L. Gunshor
Surface Science267p.181 - 1861992年01月-
ISSN:396028
概要:Atomic structures of three Ga2Se3epilayers grown on GaAs(100) or ZnSe(100) epilayers by molecular beam epitaxy were studied by transmission electron microscopy. A new vacancy ordered structure was found in the heteroepitaxial interface regions of Ga2Se3epilayers. The ordered structure is described as an alternate stacking of two types of Ga planes in the growth direction. One half of the sites are vacancies in one type of Ga plane, while the other type of Ga plane is fully occupied by Ga atoms. Comparison of three Ga2Se3epilayers indicates a strong influence of surface chemistry of substrate epilayers on the formation of the vacancy ordering. A highly developed two-dimensional ordering has occured in the epilayer grown on a GaAs(100) surface with (4 × 3) rereconstructions. ? 1992.
G.C. Hua, N. Otsuka, W. Xie, D.C. Grillo, M. Kobayashi, and R.L. Gunshor
Mat. Res. Soc. Symp. Proc.査読有り242p.208 - 2111992年00月-
W. Xie, D.C. Grillo, M. Kobayashi, R.L. Gunshor, H. Jeon, J. Ding, A.V. Nurmikko, G.C. Hua, and N. Otsuka
Mat. Res. Soc. Symp. Proc.査読有り242p.203 - 2061992年00月-
R.L. Gunshor, A.V. Nurmikko, M. Kobayashi
Physics World査読有り(3)p.46 - 501992年00月-
A.V. Nurmikko, R.L. Gunshor, M. Kobayashi
Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics査読有り10p.2056 - 20591992年00月-
R. L. Gunshor, M. Kobayashi, N. Otsuka, A. V. Nurmikko
Journal of Crystal Growth115p.652 - 6591991年12月-
ISSN:220248
概要:The paper addresses two issues related to II-VI/III-V heterostructures. The first topic is a discussion of the nature of the bonding at CdTe/InSb and ZnSe/GaAs interfaces grown by molecular beam epitaxy. The bonding is studied by means of in situ X-ray photoelectron spectroscopy (XPS). A comparison of the In 3d core level features from an InSb epilayer suface, a Te-reacted InSb surface, very thin (a few monolayers thick) CdTe/InSb epilayer/epilayer heterostructures and from deliberately grown (In, Te) epilayers, indicate that the Te-reacted layer, the CdTe/InSb heterostructures and the (In, Te) epilayers exhibit similar In bonding characteristics. A parallel XPS study of ZnSe/GaAs interfaces reinforces the conclusion that there is a general tendency for the formation of a III-VI interfacial compound when forming II-VI/III-V junctions. The second topic concerns a description of pn junction light emitting devices based on ZnSe. In the structures described, carriers are injected from nitrogen doped p-ZnSe and chlorine doped n-ZnSe into a multiple quantum well structure having (Zn,Cd)Se wells and ZnSe barriers. The bright CW photon emission originates from quantum well transitions. ? 1991.
H. Jeon, J. Ding, W. Patterson, A. V. Nurmikko, W. Xie, D. C. Grillo, M. Kobayashi, R. L. Gunshor
Applied Physics Letters59p.3619 - 36211991年12月-
ISSN:36951
概要:Laser diode action in the blue-green has been observed from (Zn,Cd)Se quantum wells within ZnSe/Zn(S,Se) p-n heterojunctions up to 250 K. Operation is reported for two different configurations for which the GaAs substrate serves either as the n- or p-type injecting contact. In pulsed operation, output powers exceeding 0.6 W have been measured in devices prepared on both n-type and p-type GaAs epitaxial buffer layers and substrates.
QIU J, MENKE D R, KOBAYASHI M, GUNSHOR R L, LI D, NAKAMURA Y, OTSUKA N
Applied Physics Letters58(24)p.2788 - 27901991年06月-
ISSN:0003-6951
QIU J, MENKE D R, KOBAYASHI M, GUNSHOR R L, LI D, NAKAMURA Y, OTSUKA N
Applied Physics Letters58(24)p.2788 - 27901991年06月-
ISSN:0003-6951
QIU J, MENKE D R, KOBAYASHI M, GUNSHOR R L, LI D, NAKAMURA Y, OTSUKA N
Applied Physics Letters58(24)p.2788 - 27901991年06月-
ISSN:0003-6951
QIU J, MENKE D R, KOBAYASHI M, GUNSHOR R L, QIAN Q‐D, LI D, OTSUKA N
Journal of Crystal Growth111(43469.0)p.747 - 7511991年05月-
ISSN:0022-0248
LI D, NAKAMURA Y, OTSUKA N, QIU J, KOBAYASHI M, GUNSHOR RL
JOURNAL OF CRYSTAL GROWTH査読有り111(43469.0)p.1038 - 10421991年05月-
ISSN:0022-0248
HAN J, DURBIN SM, GUNSHOR RL, KOBAYASHI M, MENKE DR, PELEKANOS N, HAGEROTT M, NURMIKKO AV, NAKAMURA Y, OTSUKA N
JOURNAL OF CRYSTAL GROWTH査読有り111(43469.0)p.767 - 7711991年05月-
ISSN:0022-0248
M. Kobayashi, D.R. Menke, and R.L. Gunshor
Proc. of IEEE/LEOS Summer Topical Meeting on Epitaxial Materials and In-situ Processing for Optoelectronic Devices査読有りp.51 - 521991年00月-
M. Kobayashi, R. L. Gunshor, J. L. Glenn Jr., Sungki O, J. Han, D.R. Menke, L. A. Kolodziejski, D. Li and N. Otsuka
Mat. Res. Soc. Symp. Proc.査読有り216p.227 - 2301991年00月-
G. Kudlek, N. Presser, J. Gutowski, D.L. Mathine, M. Kobayashi, and R.L. Gunshor
Proceedings of SPIE査読有り1361p.150 - 1581991年00月-
D. Li, Y. Nakamura, N. Otsuka, J. Qiu, M. Kobayashi, R.L. Gunshor
Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics査読有り9p.2167 - 21701991年00月-
D.R. Menke, J. Qiu, R.L. Gunshor, M. Kobayashi, D. Li, Y. Nakamura, N. Otsuka
Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics査読有り9p.2171 - 21751991年00月-
B. Rockwell, H.R. Chandrasekhar, M. Chandrasekhar, A.K. Ramdas, M. Kobayashi, R.L. Gunshor
Physical Review査読有り44p.11307 - 113101991年00月-
Presser, G. Kudlek, J. Gutowski, D.R. Menke, M. Kobayashi, R.L. Gunshor
Superlattices and Microstructures査読有り10(2)p.247 - 2521991年00月-
J. Qiu, Q. D. Qian, R. L. Gunshor, M. Kobayashi, D. R. Menke, D. Li, N. Otsuka
Applied Physics Letters56p.1272 - 12741990年12月-
ISSN:36951
概要:Epitaxial ZnSe/epitaxial GaAs interfaces have been formed by molecular beam expitaxy and evaluated by several techniques including capacitance-voltage measurements. In the study reported here, the GaAs surface stoichiometry was systematically varied prior to the nucleation of ZnSe. A dramatic reduction of interface state density occurred when the GaAs epilayer was made As deficient. The resulting interface state densities of as-grown structures are comparable to values obtained with (Al,Ga)As/GaAs interfaces.
D. Li, J. M. Gonsalves, N. Otsuka, J. Qiu, M. Kobayashi, R. L. Gunshor
Applied Physics Letters57p.449 - 4511990年12月-
ISSN:36951
概要:Interfaces of pseudomorphic (100) ZnSe/GaAs heterostructures grown by molecular beam epitaxy have been studied by transmission electron microscopy. The observation of three different heterostructures suggests the existence of a transition structure at the ZnSe/GaAs interfaces which have formed on As-deficient GaAs surfaces. The transition structure appears as a bright line in dark field images of the 200 reflection, while it becomes a dark line in dark field images of the 400 reflection. These observations are explained by assuming the existence of an interface layer which has a zinc blende type structure having vacancies in one of the face centered cubic sublattices.
G. Kudlek, J. Hollandt, N. Presser, J. Gutowski, S. M. Durbin, D. R. Menke, M. Kobayashi, R. L. Gunshor
Journal of Applied Physics68p.2532 - 25341990年12月-
ISSN:218979
概要:For the first time, ZnSe epitaxial layers grown by molecular-beam epitaxy are shown to exhibit large contrast, low power, and extremely long-term stable thermally induced absorptive optical bistability. It is observed over a wide temperature range between 169 K and RT, with a strongly variable loop width and a switch-back adjustable to be less than 50% of the respective switch-down value. Critical slowing down as well as switch-down times are studied in dependence of the excess over the switch-down intensity values.
W. Walecki, W. R. Patterson, A. V. Nurmikko, H. Luo, N. Samarth, J. K. Furdyna, M. Kobayashi, S. Durbin, R. L. Gunshor
Applied Physics Letters57p.2641 - 26431990年12月-
ISSN:36951
概要:We have employed short-wavelength holographic laser lithography and reactive ion etching to define wire and dot-like patterns in ZnSe thin epitaxial films and heterostructures with spatial feature size to better than 100 nm. Photoluminescence measurements suggest that surface damage from etching may be much less severe than in III-V semiconductors.
N. Pelekanos, J. Ding, Q. Fu, Arto V. Nurmikko, M. Kobayashi, R. L. Gunshor
XVII International Conference on Quantum Electronics. Digest of査読有りp.82 - 841990年12月-
概要:It has been established experimentally in a number of wide-gap II-IV semiconductors, notably ZnTe, that the recombination spectrum of photon energies at and above the bandgap often consists of well-defined peaks separated by LO phonon energies. The physical issues subject to debate have been (1) the distinction between hot luminescence (HL) and resonance Raman scattering (RRS), and (2) whether the energetically relaxing electron-hole pair maintains an excitonlike character throughout the entire secondary emission process. It is shown how the availability of a ZnTe-based quantum well with advanced experimental methods gives direct insight into this problem. Experiments were carried out on a ZnTe/MnTe single-quantum-well structure with very thin MnTe barrier layers (22 angstrom). Tunneling of electron-hole pairs out of the ZnTe quantum well strongly reduces the normal thermalized PL (photoluminescence) emission, so the entire secondary emission from the quantum well is dominated by hot luminescence. The emission, ranging from the laser excitation to the region of the n = 1 excitonic bandgap, shows how the fifth-order LO-phonon-related emission is strongly resonating at this gap. Its linewidth is considerably broadened compared with the lower orders, and a rapid loss of polarization memory with increasing order is observed. To investigate the question of exciton versus hot-electron and hole character in the secondary emission, the spectra were measured in magnetic fields up to 23 T. The key point is that, apart from small spectral shifts, the main features of the spectrum are preserved, a direct indication of the exciton nature of the process of recombination.
Q. Fu, N. Pelekanos, Arto V. Nurmikko, S. Durbin, J. Han, M. Kobayashi, R. L. Gunshor
XVII International Conference on Quantum Electronics. Digest ofp.60 - 611990年12月-
概要:A series of strained single-quantum-well (SQW) CdTe/MnTe structures with well thicknesses ranging from approximately 50 to 10 angstrom were studied. Raman experiments indicate that the lattice mismatch of approximately 3.2% is coherently accommodated if the MnTe barrier layers remain sufficiently thin (typically approximately 40 angstrom). As an example of the effects of the strong quantum confinement in these heterostructures, photoluminescence spectra (normalized amplitudes) obtained from three CdTe quantum-well samples with well thickness of approximately 22, 15, and 10 angstrom, respectively, are shown. The emissions occur in the red, yellow, and blue for the n = 1 exciton recombination in the structures. The blue emission (at approximately 478 nm) shows how confinement effects are responsible for increasing the optical gap of CdTe by approximately 1 eV. Steady-state and transient spectroscopy were applied to the quantum wells to detail the confined electronic states. An approximate conduction-to-valence band offset ratio of approximately 10:1 and excitonic binding energies in the range of 20-25 meV were inferred. Temperature-dependent linewidth studies gave a measure of the exciton-optical phonon coupling strengths that was a factor of approximately 5-8 larger than values reported for the GaAs quantum wells.
G. Kudlek, N. Presser, J. Gutowski, K. Hingerl, H. Sitter, S. M. Durbin, D. R. Menke, M. Kobayashi, R. L. Gunshor
Journal of Applied Physics68p.5630 - 56351990年12月-
ISSN:218979
概要:Comparative photoluminescence and excitation spectra of ZnSe/GaAs epilayers grown by molecular beam epitaxy (MBE) and hot-wall epitaxy (HWE) show likewise features in the exciton energy regime. Two strain-split components of the free exciton are observed, as well as characteristic sets of transitions from or into ground and excited states of acceptor- and donor-bound excitons. However, all respective lines are shifted to lower energies in the HWE samples, due to the increased thermally induced strain as a consequence of the substrate temperatures being enhanced compared to the MBE growth. Whereas the dominant donors are of the same nature in both kinds of samples, specific acceptor centers are incorporated in the HWE films. Although the MBE-grown layers are of superior quality, it is shown that HWE under optimized growth conditions is a cheap and useful alternative to obtain ZnSe epilayers of reliable properties.
Q. Fu, N. Pelekanos, A. V. Nurmikko, S. Durbin, J. Han, O. Sungki, D. Menke, M. Kobayashi, R. L. Gunshor
Surface Science229p.148 - 1501990年04月-
ISSN:396028
概要:A range of optical studies have been carried out on a series of single quantum wells of CdTe/MnTe. The structures appear to be nearly pseudomorphic and show evidence for robust electron-hole confinement. Exciton states have been characterized in terms of lifetime and coupling to optical phonons. ? 1990.
N. Pelekanos, Q. Fu, A. V. Nurmikko, S. Durbin, J. Han, O. Sungki, D. Menke, M. Kobayashi, R. L. Gunshor
Journal of Crystal Growth101p.628 - 6311990年04月-
ISSN:220248
概要:With the incorporation of cubic zincblende MnTe, a range of optical studies have been carried out on single quantum wells of ZnTe/MnTe and CdTe/MnTe. By using thin MnTe barrier layers the structures appear to be nearly pseudomorphic and show evidence for good electron-hole confinement. ? 1989.
R. L. Gunshor, A. V. Nurmikko, L. A. Kolodziejski, M. Kobayashi, N. Otsuka
Journal of Crystal Growth101p.14 - 221990年04月-
ISSN:220248
概要:New advances in epitaxial growth techniques have contributed to an improved understanding of the properties of II-VI materials and their alloys. The creation of novel heterojunctions, quantum well structures, and strained-layer superlattices, composed of II-VI/III-V and II-VI/II-VI multilayers, can be attributed to their successful epitaxial growth by molecular beam epitaxy (MBE). The objective of this paper is to discuss some recent advances in the growth of II-VI/III-V and II-VI/II-VI heterostructures, with emphasis on two particular topics. In the first, pseudomorphic epilayer/epilayer heterojunctions consisting of ZnTe on AlSb, a configuration with potential for the development of injection light emitting devices, have been grown by MBE. Microstructural and optical evaluation has indicated a high structural quality. The second topic describes the use of MBE for the growth of novel structures incorporating a previously hypothetical magnetic semiconductor, the zincblende phase of MnTe. Characterization using TEM and X-ray diffraction reveals only the zincblende phases of MnTe. Whereas bulk crystals of MnTe having a NiAs structure with a bandgap of 1.3 eV, the zincblende phase exhibits a bandgap of 3.2 eV. Single quantum well structures incorporating zincblende MnTe exhibit 2D electron and hole confinement in both CdTe and ZnTe quantum wells, and serve to confirm the zincblende MnTe bandgap at 3.2 eV. ? 1989.
D. L. Mathine, S. M. Durbin, R. L. Gunshor, M. Kobayashi, D. R. Menke, J. Gonsalves, N. Otsuka, Q. Fu, M. Hagerott, A. V. Nurmikko
Surface Science228p.344 - 3461990年04月-
ISSN:396028
概要:The difficulty in achieving the amphoteric doping of wide gap II-VI semiconductors for use in light emitting devices suggests the merits of heterojunction injection. This paper discusses the first epilayer/epilayer ZnTe/AlSb/GaSb heterojunctions grown by MBE. Pseudomorphic ZnTe layers were nucleated on pseudomorphic AlSb layers; the AlSb was grown on homoepitaxial GaSb buffer layers. Free exciton related features were observed in the photoluminescence of ZnTe; dominant features of the PL corresponded to near band-edge transitions. Microstructural quality was examined using TEM and X-ray rocking curves. Cross-sectional TEM images reveal atomically flat interfaces. X-ray rocking curve full width at half maximum values were close to the theoretically expected broadening due to the finite layer thickness. ? 1990.
N. Otsuka, D. Li, J. M. Gonsalves, C. Choi, M. Kobayashi, L. A. Kolodziejski, R. L. Gunshor
Surface Science228p.96 - 1011990年04月-
ISSN:396028
概要:Structures of ZnSe/GaAs epitaxial interfaces have been studied by cross-sectional transmission electron microscopy. Narrow dark bands are observed along these interfaces in their bright field and high resolution electron microscope images, suggesting a certain form of modifications of the structure. Despite the appearance of the dark hands, perfect coherent lattice structures are observed in high resolution images of the interfaces. Weak beam dark field images indicate the presence of lattice distortions in the neighborhood of the interfaces. These observations are explained by assuming the existence of a thin interface layer which maintain the coherent lattice relation with matrix crystals. As-grown and annealed ZnSe/GaAs epitaxial interfaces are compared in order to investigate the structural origin of the change of the electrical property of the interface by the post-growth annealing. The observation suggests that the interfacial layer remains after annealing but has changed into a slightly broader one. ? 1990.
S. Durbin, M. Kobayashi, Qiang Fu, N. Pelekanos, R. L. Gunshor, A. V. Nurmikko
Surface Science228p.33 - 361990年04月-
ISSN:396028
概要:Optical characteristics of a new metastable wide-gap II-VI semiconductor heterostructure ZnTe/MnTe are reported. Single ZnTe/MnTe quantum wells show strong n = 1 exciton resonance manifesting, for example, in pronounced enhancement of the Raman cross-section. Pseudomorphic nature of the structures is inferred from strain induced shifts in the optical phonon spectrum. ? 1990.
G. Kudlek, N. Presser, J. Gutowski, S. Durbin, D. Menke, M. Kobayashi, R. L. Gunshor
Journal of Crystal Growth101p.667 - 6721990年04月-
ISSN:220248
概要:MBE-grown ZnSe epilayers on (100) GaAs substrates are optically investigated under moderate to high excitation densities. Below the light-hole and heavy-hole exciton lines Xlhand Xhh, two lines I2and I'2are dominant in the luminescence spectra which are related to transitions from a neutral-donor-exciton complex (D0, X). For the first time, comparative excitation spectroscopy and magnetooptics of bound excitons in ZnSe epilayers allowed to determine their term structure, g-values and diamagnetic shifts. In the excitation spectra of the I2line, a set of resonances located 1.2 meV to 2.9 meV on its high-energy side can be interpreted as specific transitions into excited states of the neutral-donor-exciton complex. For excitation densities until 50 kW/cm2, high-excitation bands appear, superimposing the exciton luminescence. They are discussed to be due to exciton-exciton collision processes and can be compared with high-density transitions known from bulk ZnSe crystals. ? 1989.
J. Qiu, Q.D. Qian, R.L. Gunshor, M. Kobayashi, D.R. Menke, D. Li, N. Otsuka
Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics査読有り8(4)p.701 - 7041990年04月-
Makoto Konagai, Masakazu Kobayashi, Ryuhei Kimura, Kiyoshi Takahashi
Journal of Crystal Growth86p.290 - 2951990年01月-
ISSN:220248
概要:ZnSe-ZnTe strained superlines (SLSs) were grown by molecular beam epitaxy 9MBE). Th optical properties of the ZnSe-ZnTe SLS were evaluated by photoluminescence (PL). The PL peak position was shifted by tailoring the structure of the superlattice. The luminescence color in the visible changed from blue-green to red. In order to obtain both p- and n-type conduction in wide-bandgap II-VI compound semiconductors, we have prepared ZnSe-ZnTe superlines with a modulation doping technique. When Sb was selectively doped in ZnTe layers, all the samples exhibited p-type conductivity with hole concentrations of (0.5-1.0)X1014cm-3. On the other hand, Ga-doped SLSs were type with electron concentrations of (2-7)X1013cm-3. Furthermore, the growth of ZnSe-ZnS SLS was also demostrated by metalorganic molecular beam epitaxy (MOMBE). Blue luminescence related. to the quantized levels in the SLS was detected. ? 1988.
N. Pelekanos, Q. Fu, J. Ding, W. Wa?ecki, A. V. Nurmikko, S. M. Durbin, J. Han, M. Kobayashi, R. L. Gunshor
Physical Review B41p.9966 - 99701990年01月-
ISSN:1631829
概要:A range of optical studies has been carried out on a series of single quantum wells of CdTe/MnTe. The structures appear to be nearly pseudomorphic and show evidence for very effective electron-hole confinement. For thin quantum-well layers, efficient low-temperature photoluminescence up to yellow-green photon energies has been obtained. Coupling of excitons to longitudinal-optical phonons has also been measured. ? 1990 The American Physical Society.
R. L. Gunshor, M. Kobayashi, L. A. Kolodziejski, N. Otsuka, A. V. Nurmikko
Journal of Crystal Growth99p.390 - 3981990年01月-
ISSN:220248
概要:A pseudomorphic epilayer/epilayer heterojunction consisting of ZnTe on AlSb, having potential for the development of novel visible light emitting injection devices, has been grown by MBE. A variety of microstructural and optical evaluation techniques have provided evidence of high structural quality. The nonequilibrium growth capability of the MBE technique has enabled the growth of heterostructures incorporating a previously hypothetical widegap magnetic semiconductor, the zincblende phase of MnTe. Electron diffraction measurements of cross-sectional samples reveal only zincblende phases. Double barrier structures incorporating zincblende MnTe are found to exhibit 2D electron and hole confinement in CdTe and ZnTe quantum well layers, and serve to confirm the zincblende MnTe bandgap at 3.2 eV. ? 1990.
N. Presser, G. Kudlek, J. Gutowski, S. M. Durbin, D. R. Menke, M. Kobayashi, R. L. Gunshor
physica status solidi (b)159p.443 - 4481990年01月-
ISSN:3701972
概要:ZnSe epilayers grown by MBE on (100) GaAs substrates are optically investigated in comparison with bulk ZnSe crystals using photoluminescence and excitation spectroscopy under high excitation densities. High‐density luminescence bands appear in both materials for relatively low excitation densities (about 30 kW/cm2), but their energetic positions do not correspond. The intensity‐dependent shape, and the behaviour of the dominant band in bulk ZnSe in excitation spectroscopy are similar to that of the M band in other II VI semiconductors. The main bands growing up in the ZnSe/GaAs films are much more corresponding to typical P‐band emission of exciton‐exciton collision. Further, the transmission of ZnSe epilayers released from the GaAs substrate is studied in dependence on the laser intensity. Copyright ? 1990 WILEY‐VCH Verlag GmbH & Co. KGaA
N. Otsuka, D. Li, J. Qiu, M. Kobayashi, R. L. Gunshor
Materials Transactions, JIM31p.622 - 6271990年01月-
ISSN:9161821
概要:A series of pseudomorphic (100) ZnSe/GaAs heterostructures were grown by molecular beam epitaxy on GaAs epilayers which had different As coverages of surfaces. A large variation of the interface state density was observed among the heterostructures by capacitance-voltage measurements. Transmission electron microscope observations of cross-sectional samples have revealed existence of an interface layer in the heterostructures grown on As-deficient GaAs surfaces. Analyses of dark field images and high resolution microscope images have shown that the interface layer has a structure similar to that of Ga2Se3which crystallizes in a zincblende type structure with vacancies on the Ga sublattice. ? 1990, The Japan Institute of Metals. All rights reserved.
G. Kudlek, J. Hollandt, N. Presser, J. Gutowski, D. R. Menke, M. Kobayashi, R. L. Gunshor
Superlattices and Microstructures8p.381 - 3851990年01月-
ISSN:7496036
概要:MBE-grown ZnSe epilayers released from their GaAs substrates exhibit thermally induced absorptive optical bistability of high contrast ratios and low switching powers in a wide temperature range up to room temperature. For increasing sample thickness or for enhanced reflection realized by inserting the samples into a resonator, counteracting dispersive switching becomes visible. The interplay of both the absorptive and dispersive effects is studied for different samples and varied experimental parameters. Long-term stability of the samples with regard to all switching effects makes them promising candidates for application studies. ? 1990.
N. Pelekanos, J. Ding, Q. Fu, A.V. Nurmikko, M. Kobayashi, R.L. Gunshor
Digest of XVII international Conference on Quantum Electronics査読有りp.82 - 841990年00月-
D. Li, N. Otsuka, J. Qiu, J. Glenn Jr., M. Kobayashi, and R.L. Gunshor
Mat. Res. Soc. Symp. Proc.査読有り161p.127 - 1301990年00月-
J. Qiu, Q.-D. Qian, M. Kobayashi, R.L. Gunshor, D.R. Menke, D. Li, and N. Otsuka
Mat. Res. Soc. Symp. Proc.査読有り161p.115 - 1101990年00月-
D.L. Mathine, J. Han, M. Kobayashi, R.L. Gunshor, D.R. Menke, M. Vaziri, J. Gonsalves, N. Otsuka, Q. Fu, M. Hagerott, and A.V. Nurmikko
Mat. Res. Soc. Symp. Proc.査読有り161p.121 - 1251990年00月-
A.V. Nurmikko, R.L. Gunshor, M. Kobayashi, and L.A. Kolodziejski
査読有り招待有り1611990年00月-
QIU J, QIAN QD, KOBAYASHI M, GUNSHOR RL, MENKE DR, LI D, OTSUKA N, KOLODZIEJSKI LA
GALLIUM ARSENIDE AND RELATED COMPOUNDS 1989査読有り106p.201 - 2061990年00月-
N. Pelekanos, Q. Fu, S. Durbin, M. Kobayashi, R.L. Gunshor, A.V. Nurmikko
Journal of Crystal Growth査読有り101p.628 - 6311990年00月-
S. Venkatesan, R. F. Pierret, J. Qiu, M. Kobayashi, R. L. Gunshor, L. A. Kolodziejski
Journal of Applied Physics66p.3656 - 36601989年12月-
ISSN:218979
概要:Results of a deep-level transient spectroscopy study of Ga-doped ZnSe thin films grown by molecular-beam epitaxy are presented. Two prominent deep levels were observed in all the samples investigated. The concentration of the trap detected at 0.34 eV below the conduction-band edge was essentially independent of the doping concentration and is attributed to native defects arising from Se vacancies in the ZnSe films. The second level with an activation energy of 0.26 eV shows a very strong doping dependence and is tentatively identified as arising from dopant-site (gallium-on-zinc-site) defects complexed with selenium vacancies. Preliminary results also indicate that planar doping of ZnSe significantly reduces the concentration of the Ga-vacancy complex.
S. M. Durbin, J. Han, O. Sungki, M. Kobayashi, D. R. Menke, R. L. Gunshor, Q. Fu, N. Pelekanos, A. V. Nurmikko, D. Li, J. Gonsalves, N. Otsuka
Applied Physics Letters55p.2087 - 20891989年12月-
ISSN:36951
概要:Epilayers of the previously hypothetical zinc-blende MnTe have been grown by molecular beam epitaxy. Epitaxial layers (0.5 μm thick) of MnTe were characterized using x-ray diffraction and transmission electron microscopy; optical reflectance measurements indicate a band gap of ?3.2 eV. A series of strained single quantum well structures was fabricated with zinc-blende MnTe forming the barrier to CdTe quantum well regions; photoluminescence spectra indicate optical transitions corresponding to strong electron and hole confinement.
Q. D. Qian, J. Qiu, M. R. Melloch, J. A. Cooper, L. A. Kolodziejski, M. Kobayashi, R. L. Gunshor
Applied Physics Letters54p.1359 - 13611989年12月-
ISSN:36951
概要:The capacitance-voltage (C-V) and the current-voltage characteristics of metal/ZnSe/p-GaAs capacitors have been investigated; both epitaxial layers were grown by molecular beam epitaxy. In the capacitor structures highly resistive, stoichiometric ZnSe functioned as the pseudoinsulator on the doped GaAs layers. The capacitance-voltage measurements demonstrated that the capacitors could be biased from accumulation through depletion, and into deep depletion, with current in the range of 10-8A cm-2. Very little frequency dispersion was observed in the C-V data when measured from 1 kHz to 1 MHz. From the high-frequency C-V curve, the surface state density as a function of position in the GaAs band gap was determined. Surface state densities were comparable to densities reported for (Al,Ga)As/GaAs heterojunctions.
D. L. Mathine, S. M. Durbin, R. L. Gunshor, M. Kobayashi, D. R. Menke, Z. Pei, J. Gonsalves, N. Otsuka, Q. Fu, M. Hagerott, A. V. Nurmikko
Applied Physics Letters55p.268 - 2701989年12月-
ISSN:36951
概要:A series of pseudomorphic ZnTe/AlSb/GaSb epilayer/epilayer heterostructures, aimed at the realization of novel wide band-gap light-emitting devices, was grown by molecular beam epitaxy. The structures were evaluated by several techniques including transmission electron microscopy (TEM), x-ray rocking curves, photoluminescence (PL), and Raman spectroscopy. Reflection high-energy electron diffraction intensity oscillations were observed during nucleation of ZnTe. The presence of dislocation-free pseudomorphic structures was confirmed by TEM. The PL spectra of ZnTe epilayers showed dominant near-band-edge features composed of free and shallow impurity bound excitons.
R. L. Gunshor, L. A. Kolodziejski, M. Kobayashi, N. Otsuka, A. V. Nurmikko
Proceedings of SPIE - The International Society for Optical Engineering1037p.78 - 851989年03月-
ISSN:0277786X
概要:The molecular beam epitaxy (MBE) and the microstructural, optical, and electrical characterization of two technologically important heterojunctions, the CdTe/InSb and the ZnSe/GaAs, are described. The II-VI/III-V heterointerface is formed by the epitaxial growth of each layer in either separate MBE growth chambers, or by each layer growth occurring in a single growth chamber. For the case where separate growth chambers are used, the active interface is preserved by employing passivation techniques, or by transferring the sample between growth chambers in an ultrahigh vacuum transfer module. The aforementioned growth approaches allow for the formation of an ‘epitaxial’ heterojunction, to be utilized as an active part of a heterojunction device. The CdTe/InSb heterointerface is approximately lattice matched (<0.05% mismatch), and is motivated by possible device applications provided by InSb quantum wells. The low temperature growth of InSb quantum wells is achieved by the use of an antimony cracking oven to provide Sb2molecules for the growth. No clear indication of mixed interfacial layers of In2Te3is observed by Raman spectroscopy or transmission electron microscopy. The ZnSe/GaAs heterointerface, having a 0.25% lattice constant mismatch, has potential for use in passivation of GaAs devices. The highly resistive, stoichiometric ZnSe is employed as an insulator in two GaAs device configurations: a field effect transistor structure and a metal-insulator-semiconductor capacitor. Electrical characteristics of the ZnSe/GaAs interface provide evidence of the electrical integrity, with measurements of the interface state density resulting in numbers comparable to those reported for the (A1, Ga)As/GaAs interface. ? 1989, SPIE.
Q. D. Qian, J. Qiu, J. L. Glenn, Sungki O, R. L. Gunshor, L. A. Kolodziejski, M. Kobayashi, N. Otsuka, M. R. Melloch, J. A. Cooper, M. Haggerott, T. Heyen, A. V. Nurmikko
Journal of Crystal Growth95p.567 - 5711989年02月-
ISSN:220248
概要:The integration of several optoelectronic device functions onto a common substrate material is an area which is currently being actively pursued. In an effort to achieve this objective, experiments are under way to examine the epitaxial growth and material properties of a variety of both II-VI and III-V compounds grown on a substrate where the II-VI/III-V heterostructure can be utilized. This paper describes some recent developments involving the molecular beam epitaxial (MBE) growth and characterization of two important II-VI/III-V heterostructures, CdTe/InSb and ZnSe/GaAs. The structures are formed taking three approaches, by using (i) surface passivation techniques, combined with transfer in air from one chamber to the other, (ii) separate growth chambers connected by an ultrahigh vacuum transfer module, and (iii) both III-V and II-VI growth is performed in the same growth chamber. Multiple quantum wells of InSb have been grown at low temperatures of 300°C, using either Sb4or Sb2(the Sb2originates from an antimony cracker). Electrical characterization of metal/pseudomorphic ZnSe/p-GaAs capacitor structures illustrates accumulation, depletion and deep depletion; high frequency capacitance versus voltage data indicate interface state densities for the ZnSe/GaAs interface to be comparable to those reported for (Al,Ga)As/GaAs interfaces. The following paper represents a combined summary of two papers presented at the 5th International Conference on Molecular Beam Epitaxy. ? 1989.
R.L. Gunshor, L.A. Kolodziejski, M. Kobayashi, A.V. Nurmikko, and N. Otsuka
Mat. Res. Soc. Symp. Proc.査読有り151p.141 - 1441989年00月-
Q.-D. Qian, J. Qiu, M. Kobayashi, R.L. Gunshor, L.A. Kolodziejski, M.R. Melloch, J.A. Cooper, Jr., J.M. Gonsalves, and N. Otsuka
Mat. Res. Soc. Symp. Proc.査読有り145p.423 - 4261989年00月-
.L. Glenn, Jr., Sungki O, L.A. Kolodziejski, R.L. Gunshor, M. Kobayashi
Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics査読有り7p.249 - 2521989年00月-
Q.-D. Qian, J. Qiu, M. Kobayashi, R.L. Gunshor, M.R. Melloch, J.A. Cooper, Jr.
Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics査読有り7p.793 - 7981989年00月-
Akira Imai, Masakazu Kobayashi, Shiro Dosho, Makoto Kongai, Kiyoshi Takahashi
Journal of Applied Physics64p.647 - 6501988年12月-
ISSN:218979
概要:A detailed study has been made of interdiffusion in ZnSe-ZnTe strained-layer superlattices (SLSs) grown by molecular-beam epitaxy (MBE) at a growth temperature of 320°C. In x-ray diffraction measurements, the satellite peak intensities relative to the zero-order peak intensity decreased with annealing time. The interdiffusion coefficient D was calculated assuming a linear diffusion model. The values of D=3.6×10-21to 2.2×10-19cm2/s at an annealing temperature of 500°C were obtained for the ZnSe-ZnTe SLSs. In the high-resolution transmission electron microscopy (HRTEM) image of as-grown SLSs, the presence of fine superlattice structures was seen, but for interdiffused samples stripes due to the periodic superlattice structures were not visible and many dislocation lines were observed. These results suggest that the structure of SLSs is significantly modulated by thermal annealing at a temperature higher than the growth temperature.
Masakazu Kobayashi, Shiro Dosho, Akira Imai, Ryuhei Kimura, Makoto Konagai, Kiyoshi Takahashi
Superlattices and Microstructures4p.221 - 2251988年01月-
ISSN:7496036
概要:ZnSe and ZnTe semiconducting materials are highly promising candidates for the fabrication of short-wavelength light-emitting devices. We have grown ZnSeZnTe strained-layer superlattices (SLSs) on InP substrates by molecular beam epitaxy. In addition to undoped SLSs, two kinds of modulation doped SLS samples were prepared in this study, the first with Ga-doped ZnSe layers and undoped ZnTe layers, and the second with undoped ZnSe layers and Sb-doped ZnTe layers. Van der Pauw measurements of the SLS samples at room temperature showed that their electrical properties can be controlled by using the modulation doping technique. The undoped sample and the Ga-doped sample exhibited n-type conduction, whereas p-type conduction was observed for the Sb-doped sample. Interdiffusion profiles of dopants were measured by secondary ion mass spectroscopy, and significant Ga redistribution was observed. Finally, we have fabricated pn junctions from ZnSeZnTe SLSs, and measured their current-voltage characteristics. ? 1988.
J.M. Gonsalves, N. Otsuka, J. Qiu, M. Kobayashi, R.L. Gunshor, and L.A. Kolodziejski
Proc. MRS Meeting査読有り1988年00月-
Masakazu Kobayashi, Makoto Konagai, Kiyoshi Takahashi, Kazuyori Urabe
Journal of Applied Physics61p.1015 - 10221987年12月-
ISSN:218979
概要:Lattice strain and lattice dynamics of ZnSe-ZnTe strained-layer superlattices (SLSs) were examined by means of transmission electron microscopy and Raman scattering. Superlattice structures were confirmed from both transmission electron diffraction patterns and bright field images of the samples. Lattice distortions which originated from misfit strains were observed by the lattice image mode. The crystallinity of the adjacent layers was degraded when the layer thickness became large and polycrystalline structures were observed when the layer thickness exceeded the critical layer thickness. Raman scattering was used to assess the magnitude of the strain in the SLSs. Optical phonon frequencies of the components in SLSs were different from those frequencies of the bulk materials. The frequency shifts were used to quantify the strains in the SLSs. The observed shifts corresponded to the calculated values.
Masakazu Kobayashi, Shiro Dosho, Akira Imai, Ryuhei Kimura, Makoto Konagai, Kiyoshi Takahashi
Applied Physics Letters51p.1602 - 16041987年12月-
ISSN:36951
概要:The conduction types of ZnSe-ZnTe strained-layer superlattices (SLS's) have been controlled by using the modulation doping technique. Two kinds of modulation-doped SLS's were prepared. One of them consisted of gallium (Ga) doped ZnSe layers and undoped ZnTe layers. The other consisted of undoped ZnSe layers and antimony (Sb) doped ZnTe layers. The conduction types of the samples modulation doped with Ga and Sb were shown to be n and p type, respectively whereas the undoped samples exhibited n-type conduction. The electrical properties of the undoped and modulation-doped samples were evaluated by the van der Pauw method. The carrier concentrations of all types of samples were about 5×1013/cm3at room temperature. The temperature dependence of the electrical properties was measured for an undoped sample and a sample modulation doped with Sb. The carrier concentrations increased with temperature and reached about 1×1017/cm3at 500 K.
R. Kimura, S. Dosho, A. Imai, M. Kobayashi, M. Konagai, K. Takahashi
Proceedings of SPIE - The International Society for Optical Engineering792p.112 - 1161987年08月-
ISSN:0277786X
概要:In order to obtain both p- and n-type conduction in a wide-bandgap II-VI compound semiconductor, we have prepared ZnSe-ZnTe strained-layer superlattices (SLS) by MBE with a modulation doping technique. Modulation-doped superlattices were analyzed by photoluminescence (PL) and the van der Pauw method. The effect of strain on the film quality induced in the SLS structure by lattice mismatch was investigated. Furthermore, the SLS structure has been directly observed by Transmission Electron Microscopy (TEM). ? 1987 SPIE.
Masakazu Kobayashi, Rhuhei Kimura, Makoto Konagai, Kiyoshi Takahashi
Journal of Crystal Growth81p.495 - 5001987年02月-
ISSN:220248
概要:ZnSe-ZnTe strained-layer superlattices (SLSs) were grown on InP, GaAs and InAs substrates by molecular beam epitaxy (MBE). The samples were characterized by transmission electron microscopy (TEM) observation, and photoluminescence (PL) measurement techniques. Uniform and fine superlattice structures were confirmed by TEM observation. Moreover, a distinguishable change in the direction of (111) lattice-fringes from ZnSe layer to ZnTe layer was clearly observed in lattice image observation. The PL peak energy depended on the thickness of the alternating layers and the luminescence was related to the size quantization of the SLS structure. The luminescence peak was also affected by the substrate materials. ? 1987.
Masakazu Kobayashi, Naoki Mino, Hironori Katagiri, Ryuhei Kimura, Makoto Konagai, Kiyoshi Takahashi
Applied Physics Letters48p.296 - 2971986年12月-
ISSN:36951
概要:A ZnSe-ZnTe strained-layer superlattice (SLS) was grown on an InP substrate by molecular beam epitaxy for the first time. The x-ray diffraction measurement technique was used to confirm the existence of the high quality SLS structure. Overall quality may also be inferred from the observed quantum size effects of the photoluminescence data.
Masakazu Kobayashi, Naoki Mino, Hironori Katagiri, Ryuhei Kimura, Makoto Konagai, Kiyoshi Takahashi
Journal of Applied Physics60p.773 - 7781986年12月-
ISSN:218979
概要:Optical properties of ZnSe-ZnTe strained-layer superlattice (SLS) grown on InP substrates were evaluated by photoluminescence. The luminescence peak intensity and position were affected by the photoexcitation intensity. The line shape was also affected by the growth temperature. The peak position was shifted by tailoring the structure of the superlattice, but it did not correlate exactly with previously reported theoretical values. We have reconsidered their data, and a better result on theoretical calulation was achieved. The luminescence color changed in the visible region from green to red. This SLS could be a new material for optoelectronic devices.
Naoki Mino, Masakazu Kobayashi, Makoto Konagai, Kiyoshi Takahashi
Journal of Applied Physics59p.2216 - 22211986年12月-
ISSN:218979
概要:ZnSe thin films were grown by plasma-assisted metalorganic chemical vapor deposition (MOCVD). Plasma-assisted MOCVD is a technique combining rf glow discharge decomposition (at 13.56 MHz) with conventional metalorganic chemical vapor deposition. This process may offer several advantages such as low-temperature growth, high chemical reactivity, cleaning effect of substrate surface, and good surface morphology. The metalorganic sources used were diethylzinc and diethylselenide. The epitaxial films were obtained at the low substrate temperature of 250 °C by plasma-assisted MOCVD. The grown films showed excellent surface morphology and uniformity over a large area. These films were applied to Al/ZnSe:Mn/ITO (indium tin oxide) dc-operated electroluminescent cells. As a manganese source, di-π-cyclopentadienyl manganese [(C5H5)2Mn] was successfully used.
Masakazu Kobayashi, Naoki Mino, Makoto Konagai, Kiyoshi Takahashi
Surface Science174p.550 - 5551986年08月-
ISSN:396028
概要:A ZnSe-ZnTe strained layer superlattice (SLS) was grown by molecular beam epitaxy with a 7% lattice mismatch between the components of SLS. InP was used as a substrate material and there was a mismatch of only 3.5% between the components of the SLS and InP. ZnSe was expanded and ZnTe was compressed. Thus the strain was accommodated by the SLS structure and a high-quality superlattice was prepared. Reflective high-energy electron diffraction and X-ray measurements indicated that a high-quality SLS was successfully grown. The superlattice structure was also confirmed by photoluminescence (PL) measurements. Moreover, an interesting phenomenon was observed from the temperature dependence of PL intensity. Strong luminescence was obtained only at a temperature of around 60 K from several samples. ? 1986.
Hironori Katagiri, Masakazu Kobayashi, Naoki Mino, Kazuyori Urabe, Makoto Konagai, Kiyoshi Takahashi
Transactions of the Institute of Electronics and Communication Engineers of Japan. Section EE69p.277 - 2781986年04月-
ISSN:0387236X
概要:Direct observation of ZnSe-ZnTe strained layer superlattice was performed by transmission electron microscopy. The long periodicity of the superlattice was confirmed by the satellite spots of transmissin electron diffraction. The bright field TEM image indicated the superlattice structure without large scale misfit dislocations.
小林 正和, 高橋 清
応用物理55(6)p.595 - 6001986年00月-
ISSN:0369-8009
概要:超格子は新しい機能性材料として大きな注目をあびている.本稿では,ひずみ超格子の概念や歴史的経過,設計指針などについて述べる.また,現在までに研究・発表されている各種ひずみ超格子について,その基礎物性を紹介する.
Masakazu Kobayashi, Naoki Mino, Makoto Konagai, Kiyoshi Takahashi
Journal of Applied Physics57p.2905 - 29081985年12月-
ISSN:218979
概要:ZnSe:Mn dc thin-film electroluminescent (EL) devices were prepared by a molecular beam growth method on glass substrates coated with transparent conductive oxide. We found that the EL properties were affected by the grade of the oxide. The EL properties were found to depend on the range of indium diffusion from the oxide to the ZnSe:Mn host layer. The effective thickness of the host layer was varied by the In diffusion. Based upon these results, we have proposed a new type of dc thin-film EL cell, namely an Al/ZnSe:Mn/ZnSe:In/oxide structure. A ZnSe:In layer was prepared as a buffer layer that would improve the crystallinity of the ZnSe:Mn host layer.
Naoki Mino, Masakazu Kobayashi, Makoto Konagai, Kiyoshi Takahashi
Journal of Applied Physics58p.793 - 7961985年12月-
ISSN:218979
概要:ZnSe thin films were grown on (100) and (111) oriented Si substrates by molecular beam epitaxy. The single-crystalline ZnSe films were obtained in the substrate temperature range of 300-450°C. The epitaxial layers were evaluated by reflection high-energy electron diffraction, x-ray diffraction, etch pit density, photoluminescence, and Hall effect measurements. Etch pit density was estimated to be 3×105cm-2. The carrier concentration and electron mobility of the epitaxial ZnSe layers at room temperature are 1.3×1017-2.8×1017cm-3and 170-250 cm2/V s, respectively. These epitaxial films were applied to Au/ZnSe:Mn/Si dc-operated electroluminescent cells. The maximum quantum efficiency of 2.2×10-2(30.4 V, 6.3×10-5A/cm2) was achieved.
Masakazu Kobayashi, Naoki Mino, Hajime Inuzuka, Makoto Konagai, Kiyoshi Takahashi
Journal of Applied Physics57p.4706 - 47101985年12月-
ISSN:218979
概要:Two types of ZnSe:Mn dc thin-film electroluminescent (EL) devices were prepared by molecular beam growth: a Au/ZnSe:Mn/GaAs cell with a single-crystal ZnSe:Mn host layer and an Al/ZnSe:Mn/ITO cell with a polycrystal ZnSe:Mn host layer. Modulation doping was used to investigate the active region in the ZnSe:Mn layer. It was found that threshold voltage characteristics of the Au/ZnSe:Mn/GaAs cell were influenced by the Mn doping position in the ZnSe host layer, but in the Al/ZnSe:Mn/ITO cell, there was no dependence of threshold voltage on the Mn doping position. The dependence of luminescence intensity-injection current characteristics on the Mn doping position showed that the excitation probability of Mn luminescence centers by injected electrons increased in the region close to the negative electrode for both types of EL cells.
Naoki Mino, Masakazu Kobayashmi, Makoto Konagai, Kiyoshi Takahashi
Japanese Journal of Applied Physics24p.383 - 3851985年01月-
ISSN:214922
概要:Al/ZnSe: Mn/ITO (indium tin oxide) dc-electroluminescent cells were fabricated by plasma-assisted organometallic chemical vapor deposition. As a new manganese source, di-lr-cyclopentadienyl manganese [(C, H), Mn] was successfully used for the first time. ? 1985 IOP Publishing Ltd.
Aya Uruno, and Masakazu Kobayashi
61st Electronic Materials Conference2019年06月26日
国際会議口頭発表(一般)
KOBAYASHI, Masakazu
2019 MRS Spring Meeting2019年04月22日
国際会議口頭発表(一般)
宇留野彩, 小林正和
電気学会全国大会講演論文集(CD-ROM)2019年03月01日
宇留野彩, 小林正和, 小林正和
応用物理学会春季学術講演会講演予稿集(CD-ROM)2019年02月25日
Aya Uruno Masakazu Kobayashi
21st International Conference on Ternary and Multinary Compounds2018年09月00日
国際会議口頭発表(一般)
Masakazu Kobayashi
20th International Conference on Molecular Beam Epitaxy招待有り2018年09月00日
国際会議口頭発表(一般)
K. Moriuchi S. Taki A. Uruno M. Kobayashi
The 18th IEEE International Conference on Nanotechnology2018年06月00日
国際会議ポスター発表
Aya Uruno Masakazu Kobayashi
7th edition of the World Conference on Photovoltaic Energy Conversion 2018年06月00日
国際会議ポスター発表
Aya Uruno Masakazu Kobayashi
Compound Semiconductor Week (CSW) 20182018年05月00日
国際会議ポスター発表
宇留野 彩 桜川 陽平 小林 正和
第65回応用物理学会春季学術講演会 2018年03月00日
国内会議口頭発表(一般)
吉野文也・宇留野 彩・桜川陽平・小林正和
平成30年電気学会全国大会2018年03月00日
国内会議口頭発表(一般)
Shunya Taki Kota Moriuchi Aya Uruno Masakazu Kobayashi
2017 MRS FALL MEETING & EXHIBIT2017年11月00日
国際会議ポスター発表
A. Uruno Y. Sakurakawa M. Kobayashi
The 27th Photovoltaic Science and Engineering Conference2017年11月00日
国際会議ポスター発表
A. Uruno Y. Sakurakawa M. Kobayashi
The 2017 U.S. Workshop on the Physics and Chemistry of II-VI Materials2017年10月00日
国際会議口頭発表(一般)
S. Taki K. Moriuchi A. Uruno M. Kobayashi
18th International Conference on II-VI Compound and Related Materials2017年09月00日
国際会議ポスター発表
T. Nakasu M. Kobayashi T. Asahi
18th International Conference on II-VI Compound and Related Materials2017年09月00日
国際会議ポスター発表
S. Taki K. Moriuchi A. Uruno M. Kobayashi
The European Materials Research Society 2017年09月00日
国際会議ポスター発表
宇留野彩 桜川陽平小林正和
第78回応用物理学会秋季学術講演会2017年09月00日
国内会議口頭発表(一般)
桜川陽平 宇留野彩 小林正和
第78回応用物理学会秋季学術講演会2017年09月00日
国内会議口頭発表(一般)
森内洸太 瀧駿也 宇留野彩 小林正和
第78回応用物理学会秋季学術講演会2017年09月00日
国内会議口頭発表(一般)
中須大蔵 小林正和 朝日聡明
第78回応用物理学会秋季学術講演会招待有り2017年09月00日
国内会議口頭発表(一般)
T. Nakasu M. Kobayashi T. Asahi
59th Annual Electronic Materials Conference2017年06月00日
国際会議口頭発表(一般)
中須大蔵 小高圭佑 小林正和 朝日聡明
第64回応用物理学会春季学術講演会2017年03月00日
国内会議口頭発表(一般)
宇留野彩 鬼界伸一郎 末次由里 桜川陽平 小林正和
第64回応用物理学会春季学術講演会2017年03月00日
国内会議口頭発表(一般)
鬼界伸一郎、宇留野彩、笹原宏希、小林正和
平成29年電気学会全国大会2017年03月00日
国内会議口頭発表(一般)
瀧 駿也 森内 洸太 宇留野 彩 張 険峰 小林 正和
平成29年電気学会全国大会2017年03月00日
国内会議口頭発表(一般)
Y. Sakurakawa A. Uruno M. Kobayashi
44th Conference on the Physics and Chemistry of Surfaces and Interfaces2017年01月00日
国際会議口頭発表(一般)
W. Sun T. Nakasu K. Odaka M. Kobayashi T. Asahi
44th Conference on the Physics and Chemistry of Surfaces and Interfaces2017年01月00日
国際会議口頭発表(一般)
中須大蔵 小林正和 朝日聡明
第5回結晶工学未来塾研究ポスター発表会2016年11月07日
国内会議口頭発表(一般)
A. Uruno Y. Sakurakawa M. Kobayashi
The 2016 U.S. Workshop on the Physics and Chemistry of II-VI Materials2016年10月00日
国際会議口頭発表(一般)
T. Nakasu W. Sun M. Kobayashi T. Asahi
32nd North American Molecular Beam Epitaxy Conference2016年09月00日
国際会議ポスター発表
T. Nakasu W. Sun M. Kobayashi T. Asahi
19th International Conference on Molecular Beam Epitaxy2016年09月00日
国際会議口頭発表(一般)
瀧 駿也 宇留野 彩 張険峰 小林 正和
第77回応用物理学会秋季学術講演会2016年09月00日
国内会議口頭発表(一般)
宇留野彩 桜川陽平 小林正和
第77回応用物理学会秋季学術講演会2016年09月00日
国内会議口頭発表(一般)
中須大蔵 孫惟哲 小林正和 朝日聡明
第77回応用物理学会秋季学術講演会2016年09月00日
国内会議口頭発表(一般)
S. Taki Y. Umejima A. Uruno X. Zhang M. Kobayashi
16th International Conference on Nanotechnology (IEEE NANO 2016)2016年08月00日
国際会議口頭発表(一般)
T. Nakasu W. Sun M. Kobayashi T. Asahi
18th International Conference on Crystal Growth and Epitaxy2016年08月00日
国際会議口頭発表(一般)
A. Uruno M. Kobayashi
The 43rd IEEE Photovoltaic Specialists Conference (PVSC43)2016年06月00日
国際会議ポスター発表
T. Nakasu S. Hattori Y. Hashimoto W. Sun J. Wang M. Kobayashi T. Asahi
58th Electronic Materials Conference2016年06月00日
国際会議口頭発表(一般)
A. Uruno S. Kikai Y. Suetsugu M. Kobayashi
43rd International Symposium on Compound Semiconductors2016年06月00日
国際会議ポスター発表
T. Nakasu T. Kizu W. Sun F. Kazami M. Kobayashi T. Asahi
43rd International Symposium on Compound Semiconductors2016年06月00日
国際会議ポスター発表
宇留野彩 小林正和
第63回応用物理学会春季学術講演会2016年03月00日
国内会議口頭発表(一般)
梅嶋悠人 瀧駿也 上村一生 宇留野彩 張険峰 小林正和
第63回応用物理学会春季学術講演会2016年03月00日
国内会議口頭発表(一般)
風見蕗乃 孫惟哲 王兢 中須大蔵 服部翔太 木津健 橋本勇輝 玉川陽菜 小高圭佑 山本洋輔 小林正和 朝日聡明
第63回応用物理学会春季学術講演会2016年03月00日
国内会議口頭発表(一般)
中須大蔵 服部翔太 木津健 橋本勇輝 孫惟哲 風見蕗乃 王兢 山本洋輔 玉川陽菜 小高圭佑 小林正和 朝日聡明
第63回応用物理学会春季学術講演会2016年03月00日
国内会議口頭発表(一般)
中須大蔵 木津健 服部翔太 橋本勇輝 孫惟哲 風見蕗乃 王兢 小高圭佑 玉川陽菜 山本洋輔 小林正和 朝日聡明
第63回応用物理学会春季学術講演会2016年03月00日
国内会議口頭発表(一般)
鬼界伸一郎 宇留野彩 末次由里
平成28年電気学会全国大会2016年03月00日
国内会議口頭発表(一般)
風見蕗乃 孫惟哲 王兢 中須大蔵 服部翔太 木津健 橋本勇輝 小林正和 朝日聡明
平成28年電気学会全国大会2016年03月00日
国内会議口頭発表(一般)
玉川陽菜 中須大蔵 服部翔太 木津健 橋本勇輝 小高圭佑 山本洋輔 孫惟哲 風見蕗乃 王兢 小林正和 朝日聡明
平成28年電気学会全国大会2016年03月00日
国内会議口頭発表(一般)
S. Hattori T. Nakasu T. Kizu Y. Hashimoto W. Sun F. Kazami M. Kobayashi T. Asahi
The 43rd Conference on the Physics and Chemistry of Surfaces and Interfaces2016年01月00日
国際会議口頭発表(一般)
W. Sun F. Kazami J. Wang T. Nakasu S. Hattori T. Kizu Y. Hashimoto M. Kobayashi T. Asahi
2015 MRS Fall Meeting2015年11月00日
国際会議口頭発表(一般)
Aya Uruno Masakazu kobayashi
THE U.S. WORKSHOP on the physics and chemistry of II-VI materials2015年10月00日
国際会議口頭発表(一般)
W.C. Sun F. Kazami J. Wang T. Nakasu S. Hattori T. Kizu Y. Hashimoto M. Kobayashi T. Asahi
The 2015 International Conference on Solid State Devices and Materials招待有り2015年09月00日
国際会議ポスター発表
Aya Uruno Yuji Takeda Tomohiro Inoue Masakazu Kobayashi
The 17th International Conference on II-VI Compounds2015年09月00日
国際会議口頭発表(一般)
T. Nakasu S.Yamashita T. Aiba S. Hattori T. Kizu W. Sun K. Taguri F. Kazami Y. Hashimoto S. Ozaki M. Kobayashi T. Asahi
The 17th International Conference on II-VI Compounds2015年09月00日
国際会議口頭発表(一般)
橋本 勇輝 中須 大蔵 木津 健 服部 翔太 孫 惟哲 風見 蕗乃 小林 正和 朝日 聡明
第76回応用物理学会秋季学術講演会2015年09月00日
国内会議口頭発表(一般)
服部 翔太 中須 大蔵 橋本 勇輝 木津 健 孫 惟哲 風見 蕗乃 小林 正和 朝日 聡明
第76回応用物理学会秋季学術講演会2015年09月00日
国内会議口頭発表(一般)
WeiChe Sun Fukino Kazami Jing Wang Taizo Nakasu Shota Hattori Takeru Kizu Yuki Hashimoto Masakazu Kobayashi Toshiaki Asahi
第76回応用物理学会秋季学術講演会2015年09月00日
国内会議口頭発表(一般)
Fukino Kazami Wei-che Sun Kosuke Taguri Taizo Nakasu Takayuki Aiba Sotaro Yamashita Shota Hattori Takeru Kizu Masakazu Kobayashi; Toshiaki Asahi
42nd International Symposium on Compound Semiconductors2015年06月00日
国際会議ポスター発表
57th Electronic Materials Conference 2015年06月00日
国際会議ポスター発表
57th Electronic Materials Conference 2015年06月00日
国際会議ポスター発表
古井三誉子 宇留野彩 小林正和
平成27年電気学会全国大会 2015年03月00日
国内会議口頭発表(一般)
橋本勇輝・中須大蔵・服部翔太・山下聡太郎・相場貴之・木津健孫惟哲・田栗光祐・風見蕗乃・小林正和・朝日聡明
平成27年電気学会全国大会 2015年03月00日
国内会議口頭発表(一般)
薄井綾香、宇留野彩、井上朋大、竹田裕二、小林正和
平成27年電気学会全国大会 2015年03月00日
国内会議口頭発表(一般)
井狩華奈美・梅嶋悠人・上村一生・張 険峰・小林正和
平成27年電気学会全国大会 2015年03月00日
国内会議口頭発表(一般)
WeiChe Sun Kosuke Taguri Fukino Kazami
第62回応用物理学会春季学術講演会2015年03月00日
国内会議口頭発表(一般)
風見蕗乃、孫惟哲、田栗光祐、中須大蔵、相場貴之、山下聡太朗、服部翔太、木津健、小?俊、橋本勇輝、小林正和、朝日聡明
第62回応用物理学会春季学術講演会2015年03月00日
国内会議口頭発表(一般)
中須 大蔵 山下 聡太郎 相場 貴之 木津 健 服部 翔太 孫 惟哲 田栗 光祐 風見 蕗乃 小? 峻 橋本 勇輝 小林 正和 朝日 聡明
第62回応用物理学会春季学術講演会2015年03月00日
国内会議口頭発表(一般)
山下 聡太郎 中須 大蔵 木津 健 相場 貴之 服部 翔太 孫 惟哲 田栗 光祐 風見 蕗乃 橋本 勇輝 小? 峻 小林 正和 朝日 聡明
第62回応用物理学会春季学術講演会2015年03月00日
国内会議口頭発表(一般)
木津 健 中須 大蔵 山下 聡太郎 相場 貴之 服部 翔太 孫 惟哲 田栗 光祐 風見 蕗乃 小? 峻 橋本 勇輝 小林 正和 朝日 聡明
第62回応用物理学会春季学術講演会2015年03月00日
国内会議口頭発表(一般)
相場 貴之 中須 大蔵 山下 聡太郎 服部 翔太 木津 健 孫 惟哲 田栗 光祐 風見 蕗乃 橋本 勇輝 小? 峻 小林 正和 朝日 聡明
第62回応用物理学会春季学術講演会2015年03月00日
国内会議口頭発表(一般)
宇留野彩、薄井綾香、竹田裕二、井上朋大、小林正和
第62回応用物理学会春季学術講演会2015年03月00日
国内会議口頭発表(一般)
梅嶋 悠人 井狩 華奈美 上村 一生 張険峰 小林 正和
第62回応用物理学会春季学術講演会2015年03月00日
国内会議口頭発表(一般)
宇留野彩 薄井綾香 井上朋大 竹田裕二 小林正和
第6回 半導体材料・デバイスフォーラム2014年12月00日
国内会議口頭発表(一般)
小林 正和
第6回 半導体材料・デバイスフォーラム招待有り2014年12月00日
国内会議口頭発表(一般)
Aya Uruno Ayaka Usui Masakazu Kobayashi
The 2014 II-VI Workshop2014年10月00日
国際会議口頭発表(一般)
A. Uruno A. Usui M. Kobayashi
19th International Conference on Ternary and Multinary Compounds 2014年09月00日
国際会議口頭発表(一般)
T. Nakasu T. Aiba S. Yamashita S. Hattori W-C. Sun K. Taguri F. Kazami M. Kobayashi T. Asahi
18th International Conference on Molecular Beam Epitaxy2014年09月00日
国際会議口頭発表(一般)
宇留野彩 薄井綾香 竹田裕二 井上朋大 小林正和
第75回応用物理学会秋季学術講演会2014年09月00日
国内会議口頭発表(一般)
服部翔太 中須大蔵 山下聡太郎 相場貴之 孫惟哲 田栗光祐 風見蕗乃 木津 健 小林正和 朝日聡明 武井勇樹 宇高勝之
第75回応用物理学会秋季学術講演会2014年09月00日
国内会議口頭発表(一般)
山下聡太郎 中須大蔵 相場貴之 服部翔太 孫 惟哲 田栗光祐 風見蕗乃 木津 健 小林正和 朝日聡明
第75回応用物理学会秋季学術講演会2014年09月00日
国内会議口頭発表(一般)
中須大蔵 山下聡太郎 相場貴之 服部翔太 孫 惟哲 田栗光祐 風見蕗乃 木津 健 小林正和 朝日聡明
第75回応用物理学会秋季学術講演会2014年09月00日
国内会議口頭発表(一般)
MIYOKO FURUI Y. UMEJIMA M. KOBAYASHI
The 2014 International Conference on Nanoscience + Technology 2014年07月00日
国際会議口頭発表(一般)
Taizo Nakasu Takayuki Aiba Sotaro Yamashita Shota Hattori Wei-Che Sun Kosuke Taguri Fukino Kazami Masakazu Kobayashi Toshiaki Asahi
56th Electronic Materials Conference2014年06月00日
国際会議ポスター発表
Uruno Aya Usui Aya Takeda Yuji Inoue Tomohiro Kobayashi Masakazu
41st International Symposium on Compound Semiconductors2014年05月00日
国際会議口頭発表(一般)
宇留野彩 薄井綾香 井上朋大 竹田裕二 小林正和
第61回応用物理学会春季学術講演会2014年03月00日
国内会議口頭発表(一般)
宇留野彩 薄井綾香 竹田裕二 井上朋大 小林正和
第61回応用物理学会春季学術講演会2014年03月00日
国内会議口頭発表(一般)
中須大蔵 山下聡太郎 相場貴之 孫 惟哲 田栗光祐 服部翔太 風見蕗乃 小林正和 都甲浩芳 朝日聡明
第61回応用物理学会春季学術講演会2014年03月00日
国内会議口頭発表(一般)
相場貴之 中須大蔵 山下聡太郎 孫 惟哲 田栗光祐 服部翔太 風見蕗乃 小林正和 都甲浩芳 朝日聡明
第61回応用物理学会春季学術講演会2014年03月00日
国内会議口頭発表(一般)
山下聡太郎 中須大蔵 相場貴之 孫 惟哲 田栗光祐 服部翔太 風見蕗乃 小林正和 朝日聡明 都甲浩芳
第61回応用物理学会春季学術講演会2014年03月00日
国内会議口頭発表(一般)
梅嶋悠人・古井三誉子・小林正和
平成26年電気学会全国大会2014年03月00日
国内会議口頭発表(一般)
薄井綾香・宇留野 彩・井上朋大・竹田裕二・小林正和
平成26年電気学会全国大会2014年03月00日
国内会議口頭発表(一般)
竹田裕二・宇留野 彩・薄井綾香・井上朋大・小林正和
平成26年電気学会全国大会2014年03月00日
国内会議口頭発表(一般)
A. Usui A. Uruno M. Kobayashi
41st Conference on the Physics and Chemistry of Surfaces and Interfaces2014年01月00日
国際会議口頭発表(一般)
W. Sun T. Nakasu K. Taguri T. Aiba S. Yamashita M. Kobayashi H. Togo S. Asahi
The 30th North American Conference on Molecular Beam Epitaxy 2013年10月00日
国際会議ポスター発表
Aya Uruno Ayaka Usui Masakazu Kobayashi
2013 II-VI Workshop2013年10月00日
国際会議口頭発表(一般)
Wei-Che Sun Taizo Nakasu Kousuke Taguri Takayuki Aiba Sotaro Yamashita Masakazu Kobayashi Hiroyoshi Togo Toshiaki Asahi
The 16th International Conference on II-VI Compounds and Related Materials 2013年09月00日
国際会議口頭発表(一般)
Miyoko Furui Masakazu Kobayashi
The 16th International Conference on II-VI Compounds and Related Materials 2013年09月00日
国際会議ポスター発表
Ayaka Usui Aya Uruno Masakazu Kobayashi
The 16th International Conference on II-VI Compounds and Related Materials 2013年09月00日
国際会議ポスター発表
T. Nakasu W. Sun S. Yamashita T. Aiba K. Taguri M. Kobayashi T. Asahi H. Togo
The 16th International Conference on II-VI Compounds and Related Materials 2013年09月00日
国際会議口頭発表(一般)
Aya Uruno Ayaka Usui Masakazu Kobayashi
The 16th International Conference on II-VI Compounds and Related Materials 2013年09月00日
国際会議口頭発表(一般)
田栗光祐 孫惟哲 中須大蔵 相場貴之 山下聡太郎 小林正和 朝日聡明 都甲浩芳
第74回応用物理学会秋季学術講演会2013年09月00日
国内会議口頭発表(一般)
中須大蔵 孫惟哲 山下聡太郎 相場貴之 田栗光祐 小林正和 都甲浩芳 朝日聡明
第74回応用物理学会秋季学術講演会2013年09月00日
国内会議口頭発表(一般)
宇留野彩 薄井綾香 小林正和
第74回応用物理学会秋季学術講演会2013年09月00日
国内会議口頭発表(一般)
Taizo Nakasu Masakazu Kobayashi Hiroyoshi Togo Toshiaki Asahi
The 55th Annual Electronic Materials Conference2013年06月00日
国際会議口頭発表(一般)
T. Nakasu M. Kobayashi H. Togo T. Asahi
The 40th International Symposium on Compound Semiconductors2013年05月00日
国際会議ポスター発表
A. Uruno A. Usui M. Kobayashi
The 40th International Symposium on Compound Semiconductors2013年05月00日
国際会議ポスター発表
宇留野彩、小林正和
第60回応用物理学会春季学術講演会2013年03月00日
国内会議口頭発表(一般)
中須大蔵、小林正和、都甲浩芳、朝日聡明
第60回応用物理学会春季学術講演会2013年03月00日
国内会議口頭発表(一般)
薄井綾香・宇留野彩・中田和輝・小林正和
平成25年電気学会全国大会2013年03月00日
国内会議口頭発表(一般)
宇留野 彩、薄井綾香、中田和輝、小林正和
平成25年電気学会全国大会2013年03月00日
国内会議口頭発表(一般)
古井三誉子、小林正和
平成25年電気学会全国大会2013年03月00日
国内会議口頭発表(一般)
Taizo Nakasu Masakazu Kobayashi
The 17th European Molecular Beam Epitaxy Workshop2013年03月00日
国際会議ポスター発表
Taizo Nakasu Yuki Kumagai Kimihiro Nishimura Masakazu Kobayashi
The 17th International Conference on Molecular Beam Epitaxy2012年09月00日
国際会議口頭発表(一般)
宇留野彩 小林正和
第73回応用物理学会学術講演会 2012年09月00日
国内会議口頭発表(一般)
中須大蔵、小林正和、朝日聡明
第73回応用物理学会学術講演会 2012年09月00日
国内会議口頭発表(一般)
Masakazu Kobayashi AyakaYagi Sayako Hamaguchi
IEEE 12th International Conference on Nanotechnology2012年08月00日
国際会議口頭発表(一般)
Masakazu Kobayashi Ayaka Yagi
International Conference on Nanoscience + Technology2012年07月00日
国際会議口頭発表(一般)
Aya Uruno Taizo Nakasu Masakazu Kobayashi
The Electronic Materials Conference2012年06月00日
国際会議口頭発表(一般)
Taizo Nakasu Yuki Kumagai Kimihiro Nishimura Aya Uruno Masakazu Kobayashi
The Electronic Materials Conference2012年06月00日
国際会議口頭発表(一般)
Yuki Kumagai Taizo Nakasu Kimihiro Nishimura Masakazu Kobayashi
Asia-Pacific Microwave Photonics Conference 2012年04月00日
国際会議ポスター発表
宇留野 彩・小林正和
平成24年電気学会全国大会2012年03月00日
国内会議口頭発表(一般)
熊谷裕輝 西村公宏 中須大蔵 小林正和
第59回応用物理学関係連合講演会2012年03月00日
国内会議口頭発表(一般)
中須大蔵 熊谷裕輝 西村公宏 小林正和
第59回応用物理学関係連合講演会2012年03月00日
国内会議口頭発表(一般)
宇留野彩 小林正和
第59回応用物理学関係連合講演会2012年03月00日
国内会議口頭発表(一般)
Masakazu Kobayashi
MRS Fall Meeting & Exhibit招待有り2011年11月00日
国際会議口頭発表(招待・特別)
熊谷裕輝 小林正和
第72回応用物理学会学術講演会2011年08月00日
国内会議口頭発表(一般)
Y. Kumagai M. Kobayashi
2011 International Conference on Solid State Devices and Materials2011年08月00日
国際会議口頭発表(一般)
M.Kobayashi Y. Kumagai T.Baba S.Imada
15th International Conference on II-VI Compounds 2011年08月00日
国際会議口頭発表(一般)
Masakazu Kobayashi AyakaYagi Miwa Inaguma SayakoHamaguchi
Electronic Materials Conference 2011年06月00日
国際会議口頭発表(一般)
八木彩夏 稲熊美和 浜口紗也子 小林正和
平成23年電気学会全国大会2011年03月00日
国内会議口頭発表(一般)
熊谷 裕輝 安藤 佳祐 中村 玄 長谷川 輝 小林 正和
第58回応用物理学関係連合講演会 神奈川工業大学2011年03月00日
国内会議口頭発表(一般)
浜口 紗也子 野岡ゆかり 小林 正和
第58回応用物理学関係連合講演会 2011年03月00日
国内会議口頭発表(一般)
Y. Kumagai S. Imada T. Baba M. Kobayashi
The 16th International Conference on Molecular Beam Epitaxy 2010年08月00日
国際会議口頭発表(一般)
M. Kobayashi S. Hamaguchi T. Yamamoto
World Congress on Particle Technology 2010年04月00日
国際会議口頭発表(一般)
小林信太郎 稲葉克彦 紺谷貴之 久保富活 櫻澤 翔 馬場俊彰 今田将太 小林正和
第57回応用物理学関係連合講演会2010年03月00日
国内会議口頭発表(一般)
今田将太 馬場俊彰 太田匠哉 熊谷裕輝 木原大真 小林正和
第57回応用物理学関係連合講演会2010年03月00日
国内会議口頭発表(一般)
山本琢磨 浜口紗也子 小林正和
第57回応用物理学関係連合講演会2010年03月00日
国内会議口頭発表(一般)
馬場俊彰・今田将太・木原大真・熊谷裕輝・太田匠哉・小林正和
平成22年電気学会全国大会2010年03月00日
国内会議口頭発表(一般)
S. Hamaguchi R. Takeuchi T. Yamamoto M. Kobayashi
The 16th International Display Workshops 2009年12月00日
国際会議ポスター発表
M. Kobayashi S. Imada T. Baba S. Sakurasawa
2009 II-VI Workshop2009年10月00日
国際会議口頭発表(一般)
M.Kobayashi S.Hamaguchi T.Yamamoto
4th Asian Particle Technology Symposium2009年09月00日
国際会議口頭発表(一般)
山下雄大 大観光徳 浜口紗也子 小林正和
第70回応用物理学会学術講演会 2009年09月00日
国内会議口頭発表(一般)
浜口紗也子 山本琢磨 小林正和
第70回応用物理学会学術講演会 2009年09月00日
国内会議口頭発表(一般)
S. Imada T. Baba S. Sakurasawa M. Kobayashi
The 14th International Conference on II-VI compounds 2009年08月00日
国際会議ポスター発表
山下雄大 小谷剛史 大観光徳 浜口紗也子 小林正和
第56回応用物理学関係連合講演会 2009年03月00日
国内会議口頭発表(一般)
浜口紗也子、山本琢磨、小林正和
第56回応用物理学関係連合講演会 2009年03月00日
国内会議口頭発表(一般)
加藤伸一郎 石井亮太 濱口沙也子 小林正和 宇高勝之
第56回応用物理学関係連合講演会 2009年03月00日
国内会議口頭発表(一般)
今田将太、馬場俊彰、桜沢翔、小林正和
第56回応用物理学関係連合講演会2009年03月00日
国内会議口頭発表(一般)
桜沢 翔・馬場俊彰・今田将太・小林正和
平成21年 電気学会全国大会2009年03月00日
国内会議口頭発表(一般)
Hamaguchi Sayako Kobayashi Masakazu
14th International Workshop on Inorganic and Organic Electroluminescence & 2008 International Conference on the Science and Technology of Emissive Displays and Lighting 20082008年09月00日
国際会議ポスター発表
M. Kobayashi S. Hamaguchi
International conference on nanoscience + technology2008年07月00日
国際会議口頭発表(一般)
浜口紗也子 小林正和
第55回応用物理学関係連合講演会 2008年03月00日
国内会議口頭発表(一般)
C E Kendrick M. Kobayashi S. M. Durbin
2008 International Conference On Nanoscience and Nanotechnology 2008年02月00日
国際会議ポスター発表
M. Kobayashi S. Hamaguchi
2008 International Conference On Nanoscience and Nanotechnology 2008年02月00日
国際会議口頭発表(一般)
K.Fujita M.Kobayashi H.Ohta H.Furukawa M.Niino
17th International Photovoltaic Science and Engineering Conference2007年12月00日
国際会議口頭発表(一般)
M.W. Allen C.H. Swartz M. Henseler R.J. Reeves J.B. Metson H. Von Wenckstern M. Grundmann S.A. Hafield P.H. Jefferson P.D.C. King T.D. Veal C. McConville M. Kobayashi S.M. Durbin
Symposium L of the 2007 Fall Meeting of the Materials Research Society2007年11月00日
国際会議口頭発表(一般)
Sayako Hamaguchi Shinji Ishizaki Masakazu Kobayashi
13th INTERNATIONAL CONFERENCE ON II-VI COMPOUNDS2007年09月00日
国際会議
植村亮、國本健太郎、浜口紗也子、小林正和
第68回応用物理学会学術講演会 2007年09月00日
国内会議口頭発表(一般)
浜口紗也子 小林正和
第68回応用物理学会学術講演会 2007年09月00日
国内会議口頭発表(一般)
C.E. Kendrick R. Tilley M. Kobayashi S.M. Durbin
Spring Meeting of the European Materials Research Society 2007年05月00日
国際会議口頭発表(一般)
浜口紗也子 小林正和
第54回応用物理学関係連合講演会 2007年03月00日
国内会議口頭発表(一般)
M.Kobayashi S. Ishizaki M. Uenishi
Nanotech Insight 20072007年03月00日
国際会議口頭発表(一般)
C.E. Kendrick R. Tilley M. Kobayashi S.M. Durbin
3rd International Conference on Advanced Materials and Nanotechnology 2007年02月11日
国際会議口頭発表(一般)
Chito E. Kendrick R. Tilley M. Kobayashi R. J. Reeves S. M. Durbin
MRS fall meetings Symposium I: Advances in III-V Nitride Semiconductor Materials and Devices2006年11月00日
国際会議口頭発表(一般)
C.E Kendrick P.A. Anderson R. Tilley M. Kobayashi S.M. Durbin
14th International Conference on Molecular Beam Epitaxy2006年09月00日
国際会議口頭発表(一般)
A.Ichiba M. Kobayashi
14th International Conference on Molecular Beam Epitaxy2006年09月00日
国際会議ポスター発表
C.E Kendrick P.A. Anderson P. Miller R. Tilley R.J. Reeves M. Kobayashi S.M. Durbin
2006 International Conference On Nanoscience and Nanotechnology2006年07月00日
国際会議口頭発表(一般)
一場綾 天野優 国政圭 上野純 小倉康平 小林正和
第53回応用物理学関係連合講演会 2006年03月00日
国内会議口頭発表(一般)
A. Ichiba J. Ueno K. Ogura S. Katsuta M. Kobayashi
12th INTERNATIONAL CONFERENCE ON II-VI COMPOUNDS2005年09月00日
国際会議ポスター発表
J.Ueno K.Ogura A.Ichiba S.Katsuta M.Kobayashi K.Onomitsu Y.Horikoshi
12th INTERNATIONAL CONFERENCE ON II-VI COMPOUNDS2005年09月00日
国際会議ポスター発表
石崎慎治 小林正和
第66回応用物理学会学術講演会2005年09月00日
国内会議口頭発表(一般)
M.Kobayashi S. Ishizaki M. Uenishi
International conference on nanomaterials NANO20052005年07月00日
国際会議口頭発表(一般)
上野純、勝田昇平、一場綾、小倉康平、小林正和
第52回応用物理学関係連合講演会2005年03月00日
国内会議口頭発表(一般)
岩井亮 小倉康平 小林正和 藤田和久 新野正之 太田浩一 古川裕之 犬塚博誠
第52回応用物理学関係連合講演会2005年03月00日
国内会議口頭発表(一般)
小倉康平 岩井亮 小林正和 藤田和久 新野正之 太田浩一 古川裕之 犬塚博誠
第52回応用物理学関係連合講演会2005年03月00日
国内会議口頭発表(一般)
一場綾、勝田昇平、上野純、小倉康平、小林正和
第52回応用物理学関係連合講演会2005年03月00日
国内会議口頭発表(一般)
Yusuke Kusakari Shinji Ishizaki Masakazu Kobayashi
2004 MRS fall meetings Symposium B: Progress in Semiconductor Materials IV ? Electronic and Optoelectronic Applications 2004年11月00日
国際会議口頭発表(一般)
Shinji Ishizaki Yusuke Kusakari Masakazu Kobayashi
2004 MRS fall meetings Symposium B: Progress in Semiconductor Materials IV ? Electronic and Optoelectronic Applications 2004年11月00日
国際会議ポスター発表
藤田和久 小林正和 古河裕之 太田浩一 犬塚博誠
第48回宇宙科学技術連合講演会 2004年11月00日
国内会議口頭発表(一般)
鮫島冴映子 神保直樹 小林正和
平成16年 電気学会 電子・情報・システム部門大会 2004年09月00日
国内会議口頭発表(一般)
草刈勇介 小林正和
第65回応用物理学会学術講演会2004年09月00日
国内会議口頭発表(一般)
岩井 亮 小倉康平 小林正和 藤田和久 新野正之 太田浩一 古河裕之 犬塚博誠
第65回応用物理学会学術講演会2004年09月00日
国内会議口頭発表(一般)
M. Kobayashi M. Enami J. Ueno S. Katsuta A. Ichiba
The 13th International Conference on Molecular Beam Epitaxy (MBE 2004) Conference 2004年08月00日
国際会議口頭発表(一般)
鮫島 冴映子 小林 正和
平成16年電気学会全国大会2004年03月00日
国内会議口頭発表(一般)
上西正晃、石崎慎治、小林正和
2004年春季応用物理学関係連合講演会2004年03月00日
国内会議口頭発表(一般)
上田 泰央、 鮫島 冴映子、 小林 正和
2004年春季応用物理学関係連合講演会2004年03月00日
国内会議口頭発表(一般)
堤一陽 勝田昇平 榎並正晃 廣瀬文昭 小林正和
2004年春季応用物理学関係連合講演会2004年03月00日
国内会議口頭発表(一般)
草刈勇介、小林正和
2004年春季応用物理学関係連合講演会2004年03月00日
国内会議口頭発表(一般)
勝田昇平 堤一陽 榎並正晃 廣瀬文昭 小林正和
2004年春季応用物理学関係連合講演会2004年03月00日
国内会議口頭発表(一般)
石崎慎治、上西正晃、小林正和
2004年春季応用物理学関係連合講演会2004年03月00日
国内会議口頭発表(一般)
榎並正晃 上野純 廣瀬文昭 堤一陽 勝田昇平 小林正和
2004年春季応用物理学関係連合講演会2004年03月00日
国内会議口頭発表(一般)
古河裕之、藤田和久、太田浩一、小林正和、新野正之
レーザー学会創立30周年記念 学術講演会第24回年次大会 2004年01月00日
国内会議口頭発表(一般)
藤田和久 太田浩一 小林正和 水井順一 犬塚博誠 古河裕之 山中正宣 新野正之
レーザー学会創立30周年記念 学術講演会第24回年次大会 2004年01月00日
国内会議口頭発表(一般)
鮫島冴子、小林正和、渋谷 潔、星野 英久、千代 雅子、藤沢 武彦
第24回日本レーザー医学会総会 2003年11月00日
国内会議口頭発表(一般)
M. ENAMI K. TSUTSUMI F. HIROSE S. KATSUTA M. KOBAYASHI
11th International Conference on II-VI Compounds2003年09月00日
国際会議口頭発表(一般)
藤田和久 太田浩一 水井順一 古河裕之 小林正和 山中正宣 新野正之
第64回応用物理学会学術講演会 2003年08月00日
国内会議口頭発表(一般)
上田泰央 小林正和
第64回応用物理学会学術講演会 2003年08月00日
国内会議口頭発表(一般)
上西正晃 草刈勇介 小林正和
第64回応用物理学会学術講演会 2003年08月00日
国内会議口頭発表(一般)
榎並正晃 廣瀬文昭 堤 一陽 勝田昇平 小林正和
第64回応用物理学会学術講演会 2003年08月00日
国内会議口頭発表(一般)
堤一陽 寺門洋 榎並正晃 勝田昇平 廣瀬文昭 小林正和
第50回応用物理学関係連合講演会2003年03月00日
国内会議口頭発表(一般)
榎並正晃 廣瀬文昭 寺門洋 堤一陽 勝田昇平 小林正和
第50回応用物理学関係連合講演会2003年03月00日
国内会議口頭発表(一般)
陰山孔貴、上西正晃、草刈勇介、小林正和
第50回応用物理学関係連合講演会2003年03月00日
国内会議口頭発表(一般)
K. Tsutsumi H. Terakado M. Enami M. Kobayashi
30th Conference on the Physics and Chemistry of Semiconductor Interfaces 2003年01月00日
国際会議口頭発表(一般)
上田泰央 小林正和
第63回応用物理学会学術講演会2002年09月00日
国内会議口頭発表(一般)
堤 一陽 寺門 洋 榎並正晃 小林正和
第63回応用物理学会学術講演会2002年09月00日
国内会議口頭発表(一般)
上田泰央 小林正和
第49回応用物理学関係連合講演会 2002年03月00日
国内会議口頭発表(一般)
澤田 理奈 小林雄 小林正和
第49回応用物理学関係連合講演会 2002年03月00日
国内会議口頭発表(一般)
小林正和、渋谷潔、星野英久、藤澤武彦
第48回応用物理学関係連合講演会2002年03月00日
国内会議口頭発表(一般)
寺門洋 澤田理奈 小林正和
第62回応用物理学会学術講演会 2001年09月00日
国内会議口頭発表(一般)
M. Kobayashi H. Terakado R. Sawada A. Arakawa K. Sato
10 TH INTERNATIONAL CONFERENCE ON II-VI COMPOUNDS2001年09月00日
国際会議口頭発表(一般)
M. Kobayashi K. Shibuya H. Hoshino T. Fujisawa
14TH WORLD CONGRESS OF THE INTERNATIONAL SOCIETY FOR LASER SURGERY AND MEDICINE2001年08月00日
国際会議口頭発表(一般)
小林正和、渋谷潔、星野英久、藤澤武彦
第24回日本気管支学会総会 2001年05月00日
国内会議口頭発表(一般)
小林正和、渋谷潔、星野英久、藤澤武彦
平成13年度日本分光学会春季講演会 2001年05月00日
国内会議口頭発表(一般)
M.Kobayashi K. Kitamura H. Umeya A. W. Jia A. Yoshikawa M. Shimotomai Y. Kato K. Takahashi
3rd International Symposium on Blue laser and Light Emmitting Diodes2000年03月00日
国際会議口頭発表(一般)
T. Kazama F. Yasunaga Y. Taniyasu A. Jia Y. Kato M. Kobayashi A. Yoshikawa K. Takahashi
3rd International Symposium on Blue laser and Light Emmitting Diodes2000年03月00日
国際会議口頭発表(一般)
Y. Taniyasu K. Suzuki D.H. Lim A. Jia M.Shimotomai Y. Kato M. Kobayashi A. Yoshikawa K. Takahashi
3rd International Symposium on Blue laser and Light Emmitting Diodes2000年03月00日
国内会議口頭発表(一般)
H. Umeya K. Kitamura A. W. Jia M. Kobayashi A. Yoshikawa M. Shimotomai Y. Kato K. Takahashi
International Conference on II-VI Compounds 1999年11月00日
国内会議口頭発表(一般)
K. Kitamura H. Umeya A. W. Jia M. Kobayashi A. Yoshikawa M. Shimotomai Y. Kato K. Takahashi
International Conference on II-VI Compounds 1999年11月00日
国内会議口頭発表(一般)
A. Jia T. Furushima M. Kobayashi Y. Kato M. Shimotomai A. Yoshikawa K. Takahashi
International Conference on II-VI Compounds 1999年11月00日
国内会議口頭発表(一般)
H. Zhou A.V. Nurmikko M. Kobayashi A. Yoshikawa
Conference on Lasers and Electro-Optics /Quantum Electronins and Laser Science Conference1999年05月00日
国内会議口頭発表(一般)
谷保芳孝、佐藤英史、佐藤弘人、渡邊泰弘、下山紀夫、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第46回応用物理学関係連合講演会1999年03月00日
国内会議口頭発表(一般)
林秀樹、林田章裕、秦志新、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第46回応用物理学関係連合講演会1999年03月00日
国内会議口頭発表(一般)
渡邊泰弘、谷保芳孝、佐藤英史、佐藤弘人、辻隆志、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第46回応用物理学関係連合講演会1999年03月00日
国内会議口頭発表(一般)
古島達弥、河内福賢、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第46回応用物理学関係連合講演会1999年03月00日
国内会議口頭発表(一般)
梅谷治樹、中村眞一郎、北村和也、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第46回応用物理学関係連合講演会1999年03月00日
国内会議口頭発表(一般)
中村眞一郎、北村和也、梅谷治樹、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第46回応用物理学関係連合講演会1999年03月00日
国内会議口頭発表(一般)
北村和也、中村眞一郎、梅谷治樹、賈岸偉、下斗米道夫、加藤嘉則、小林正和 、吉川明彦、高橋清
第46回応用物理学関係連合講演会1999年03月00日
国内会議口頭発表(一般)
勝康夫、有馬茂幸、林田章裕、林秀樹、木村龍平、秦志新、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第46回応用物理学関係連合講演会1999年03月00日
国内会議口頭発表(一般)
H. Zhou A.V. Nurmikko M. Kobayashi A. Yoshikawa
American Physical Society Centennial Meeting Program 1999年03月00日
国際会議口頭発表(一般)
M. Kobayashi S. Nakamura K. Kitamura H. Umeya A. Jia M. Kobayashi A. Yoshikawa M. Shimotomai Y. Kato
26th Conference on Physics and Chemistry of Semiconductor Interfaces 1999年01月00日
国際会議口頭発表(一般)
R. Kimura K. Takahashi A. W. Jia M. Kobayashi A. Yoshikawa
2nd International Symposium on Blue laser and Light Emitting Diodes1998年09月00日
国際会議口頭発表(一般)
H. Hayashi A. Hayashida Y. Sugure Z. Qin A. W. Jia M. Kobayashi M. Shimotomai Y. Kato A. Yoshikawa K. Takahashi
2nd International Symposium on Blue laser and Light Emitting Diodes1998年09月00日
国際会議口頭発表(一般)
Y. Taniyasu E. Sato H. Sato N. Shimoyama A. W. Jia M. Shimotomai Y. Kato M. Kobayashi A. Yoshikawa K. Takahashi
2nd International Symposium on Blue laser and Light Emitting Diodes1998年09月00日
国際会議口頭発表(一般)
Z. Qin H. Nagano Y. Sugure A. Jia M. Kobayashi Y. Kato A. Yoshikawa K. Takahashi
2nd International Symposium on Blue laser and Light Emitting Diodes1998年09月00日
国際会議口頭発表(一般)
梅谷治樹、中村眞一郎、北村和也、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第59回応用物理学術講演会1998年09月00日
国内会議口頭発表(一般)
林田章裕、勝康夫、秦志新、林秀樹、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第59回応用物理学術講演会1998年09月00日
国内会議口頭発表(一般)
佐藤英史、谷保芳孝、佐藤弘人、渡邊泰弘、下山紀夫、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第59回応用物理学術講演会1998年09月00日
国内会議口頭発表(一般)
谷保芳孝、佐藤英史、佐藤弘人、下山紀夫、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第59回応用物理学術講演会1998年09月00日
国内会議口頭発表(一般)
中村眞一郎、北村和也、梅谷治樹、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第59回応用物理学術講演会1998年09月00日
国内会議口頭発表(一般)
渡邊泰弘、谷保芳孝、佐藤英史、佐藤弘人、下山紀夫、辻隆志、賈岸偉、加藤嘉則、小林正和、吉川明彦、高橋清
第59回応用物理学術講演会1998年09月00日
国内会議口頭発表(一般)
M. Kobayashi K. Wakao S. Nakamura Y. Sugure A. W. Jia A. Yoshikawa M. Shimotomai Y. Kato K. Takahashi
Tenth International Conference on Molecular Beam Epitaxy 1998年08月00日
国際会議口頭発表(一般)
木村龍平、高橋清、勝康夫、永野元、秦志新、賈岸偉、小林正和、吉川明彦
第45回応用物理学関係連合講演会1998年03月00日
国内会議口頭発表(一般)
中村眞一郎、若尾和弘、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第45回応用物理学関係連合講演会1998年03月00日
国内会議口頭発表(一般)
谷保芳孝、佐藤英史、佐藤弘人、下山紀夫、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第45回応用物理学関係連合講演会1998年03月00日
国内会議口頭発表(一般)
秦志新、永野元、勝康夫、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第45回応用物理学関係連合講演会1998年03月00日
国内会議口頭発表(一般)
永野元、勝康夫、秦志新、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第45回応用物理学関係連合講演会1998年03月00日
国内会議口頭発表(一般)
若尾和弘、中村眞一郎、賈岸偉、下斗米道夫、加藤嘉則、小林正和、吉川明彦、高橋清
第45回応用物理学関係連合講演会1998年03月00日
国内会議口頭発表(一般)
Y. Nakamura T. Yamashita M. Kobayashi Y. Kato A. Yoshikawa
1995 Japan International Electronic Manufacturing Technology Symposium 1995年12月00日
国際会議口頭発表(一般)
T. Yamada C. Setiagung A.W. Jia M. Kobayashi A. Yoshikawa
15th Annual North American Conference on Molecular Beam Epitaxy 1995年09月00日
国際会議口頭発表(一般)
C. Setiagung、山田剛、賈岸偉、小林正和、吉川明彦
第56回応用物理学会学術講演会1995年08月00日
国内会議口頭発表(一般)
田中由紀夫、小松茂樹、伊藤良一、小林正和、吉川明彦
第56回応用物理学会学術講演会1995年08月00日
国内会議口頭発表(一般)
中村豊、山下寿康、小林正和、吉川明彦
第56回応用物理学会学術講演会1995年08月00日
国内会議口頭発表(一般)
山田剛、C. Setiagung、賈岸偉、小林正和、吉川明彦
第56回応用物理学会学術講演会1995年08月00日
国内会議口頭発表(一般)
M. Miyaji Y. Ohira S. Komatsu M. Kurihara N. Shimoyama M. Kobayashi Y. Kato A. Yoshikawa
7th International Conference on II-VI Compounds and Devices 1995年08月00日
国際会議口頭発表(一般)
T. Yoshida T. Nagatake M. Kobayashi A. Yoshikawa
7th International Conference on II-VI Compounds and Devices 1995年08月00日
国際会議口頭発表(一般)
T. Yoshida T. Kurusu M. Kobayashi A. Yoshikawa
14th Electronic Materials Symposium 1995年07月00日
国際会議口頭発表(一般)
T. Yoshida T. Nagatake M. Kobayashi A. Yoshikawa
37th Electric Materials Conference 1995年06月00日
国際会議口頭発表(一般)
吉田孝、長竹剛、村口昭一、来栖武志、小林正和、吉川明彦
第42回応用物理学関係連合講演会1995年03月00日
国内会議口頭発表(一般)
高橋政志、古山俊行、小林正和、吉川明彦
第42回応用物理学関係連合講演会1995年03月00日
国内会議口頭発表(一般)
賈岸偉、山田剛、伊福徹、C. Setiagung、小林正和、吉川明彦
第42回応用物理学関係連合講演会1995年03月00日
国内会議口頭発表(一般)
中村豊、秋葉学、小林正和、吉川明彦
第42回応用物理学関係連合講演会1995年03月00日
国内会議口頭発表(一般)
An W. Jia T. Yamada Masakazu Kobayashi Akihiko Yoshikawa
European workshop on II-VI compounds 1994年09月00日
国際会議口頭発表(一般)
W. Imajuku M. Takahashi M. Kobayashi A. Yoshikawa
Intn'l Workshop on Metastable and Strained Semiconductor Structures 1994年09月00日
国際会議口頭発表(一般)
小林 正和
第55回応用物理学会学術講演会1994年09月00日
国内会議口頭発表(一般)
吉田 孝、長竹 剛、小林 正和、吉川 明彦
第55回応用物理学会学術講演会1994年09月00日
国内会議口頭発表(一般)
賈 岸偉、山田剛、小林正和、吉川明彦
第55回応用物理学会学術講演会1994年09月00日
国内会議口頭発表(一般)
A. Yoshikawa M. Kobayashi S. Tokita
7th International Conference on Metalorganic Vapor Phase Epitaxy 1994年05月00日
国際会議口頭発表(一般)
A. Yoshikawa M. Kobayashi S. Tokita
3rd International Symposium on Atomic layer epitaxy and related surface processes 1994年05月00日
国際会議口頭発表(一般)
M. Kobayashi A. Yoshikawa
Materials Research Society Meeting 招待有り1994年04月00日
国際会議口頭発表(招待・特別)
今宿亙、小林正和、吉川明彦
第41回応用物理学関係連合講演会1994年03月00日
国内会議口頭発表(一般)
高橋政志、小林正和、吉川明彦
第41回応用物理学関係連合講演会1994年03月00日
国内会議口頭発表(一般)
時田茂、小林正和、吉川明彦
第41回応用物理学関係連合講演会1994年03月00日
国内会議口頭発表(一般)
A. Yoshikawa M. Kobayashi S. Tokita K. Sato
1st International Conference on Photo-Excited Processes and Applications 1993年10月00日
国際会議口頭発表(一般)
今宿亙、小林正和、吉川明彦
第54回応用物理学会学術講演会1993年09月00日
国内会議口頭発表(一般)
長竹剛、登坂裕之、小林正和、吉川明彦
第54回応用物理学会学術講演会1993年09月00日
国内会議口頭発表(一般)
小林正和、吉川明彦
第54回応用物理学会学術講演会1993年09月00日
国内会議口頭発表(一般)
A. Yoshikawa M. Kobayashi S. Tokita
3rd Japan-Korea Joint Symposium on Advanced Science and Technology for Semiconductor Materials and Devices 1993年09月00日
国際会議口頭発表(一般)
M. Kobayashi H. Tosaka T. Nagatake T. Yoshida A. Yoshikawa
6th International Conference on II-VI compounds and Related Optoelectronic Materials 1993年09月00日
国際会議口頭発表(一般)
A.W. Jia M. Kobayashi A. Yoshikawa
20th Alloy Semiconductor Physics and Electronics Symposium 1993年07月00日
国際会議口頭発表(一般)
H. Tosaka S. Matsumoto T. Nagatake T. Yoshida M. Kobayashi A. Yoshikawa
20th Alloy Semiconductor Physics and Electronics Symposium 1993年07月00日
国際会議口頭発表(一般)
S. Tokita M. Kobayashi A. Yoshikawa
4th International Conference on Chemical Beam Epitaxy and Related Growth Technique 1993年07月00日
国際会議口頭発表(一般)
A.W. Jia M. Kobayashi A. Yoshikawa
35th Electric Materials Conference 1993年06月00日
国際会議口頭発表(一般)
今宿亙、高橋政志、小林正和、吉川明彦
第40回応用物理学関係連合講演会1993年03月00日
国内会議口頭発表(一般)
登坂裕之、松本繁之、長竹剛、吉田孝、小林正和、吉川明彦
第40回応用物理学関係連合講演会1993年03月00日
国内会議口頭発表(一般)
松本繁之、登坂裕之、長竹剛、吉田孝、小林正和、吉川明彦
第40回応用物理学関係連合講演会1993年03月00日
国内会議口頭発表(一般)
徐増儀、小林正和、吉川明彦
第40回応用物理学関係連合講演会1993年03月00日
国内会議口頭発表(一般)
賈岸偉、小林正和、吉川明彦
第40回応用物理学関係連合講演会1993年03月00日
国内会議口頭発表(一般)
佐藤浩太郎、高村義明、小林正和、吉川明彦
第40回応用物理学関係連合講演会1993年03月00日
国内会議口頭発表(一般)
山口俊哉、田尾中、秦野孝行、小林正和、吉川明彦
第40回応用物理学関係連合講演会1993年03月00日
国内会議口頭発表(一般)
時田茂、宮地護、小林正和、吉川明彦
第40回応用物理学関係連合講演会1993年03月00日
国内会議口頭発表(一般)
田中丈久、松井亮、小林正和、吉川明彦
第40回応用物理学関係連合講演会1993年03月00日
国内会議口頭発表(一般)
吉川明彦、小林正和
第53回応用物理学会学術講演会1992年09月00日
国内会議口頭発表(一般)
山口俊哉、賈岸偉、小林正和、吉川明彦
第53回応用物理学会学術講演会1992年09月00日
国内会議口頭発表(一般)
佐藤浩太郎、徐増儀、小林正和、吉川明彦
第53回応用物理学会学術講演会1992年09月00日
国内会議口頭発表(一般)
松本繁之、吉田孝、登坂裕之、小林正和、吉川明彦
第53回応用物理学会学術講演会1992年09月00日
国内会議口頭発表(一般)
登坂裕之、松本繁之、吉田孝、小林正和、吉川明彦
第53回応用物理学会学術講演会1992年09月00日
国内会議口頭発表(一般)
賈岸偉、山口俊哉、小林正和、吉川明彦
第53回応用物理学会学術講演会1992年09月00日
国内会議口頭発表(一般)
時田茂、小林正和、吉川明彦
第53回応用物理学会学術講演会1992年09月00日
国内会議口頭発表(一般)
A. V. Nurmikko, Robert L. Gunshor, Nobuo Otsuka, M. Kobayashi
Conference on Solid State Devices and Materials招待有り1992年08月00日
国際会議口頭発表(招待・特別)
S. Matsumoto M. Kobayashi A. Yoshikawa
The 3rd International Conference on High Technology 1992年09月00日
国際会議口頭発表(一般)
M. Kobayashi
The 5th International Conference on Shallow Impurities in Semiconductors招待有り1992年08月00日
国際会議口頭発表(招待・特別)
R. L. Gunshor M. Kobayashi A. V. Nurmikko N. Otsuka
The 11th Alloy Semiconductor Physics and Electronics Symposium招待有り1992年07月00日
国際会議口頭発表(招待・特別)
W. Xie D.C. Grillo R.L. Gunshor M. Kobayashi N. Otsuka G.C. Hua H. Jeon J. Ding A.V. Nurmikko
March Meeting of the American Physical Society1992年03月00日
国際会議口頭発表(一般)
G.C. Hua N. Otsuka W. Xie D.C. Grillo M. Kobayashi R.L. Gunshor
Fall Meeting of Materials Research Society1991年12月00日
国際会議口頭発表(一般)
W. Xie D.C. Grillo M. Kobayashi R.L. Gunshor H. Jeon J. Ding A.V. Nurmikko G.C. Hua N. Otsuka
Fall Meeting of Materials Research Society1991年12月00日
国際会議口頭発表(一般)
W. Xie D.C. Grillo R.L. Gunshor M. Kobayashi G.C. Hua N. Otsuka H. Jeon J. Ding A.V. Nurmikko
11th Molecular Beam Workshop1991年09月00日
国際会議口頭発表(一般)
W. Xie D.C. Grillo M. Kobayashi R.L. Gunshor G.C. Hua N. Otsuka H. Jeon J. Ding A.V. Nurmikko
5th International Conference on II-VI Compounds1991年09月00日
国際会議口頭発表(一般)
A.V. Nurmikko R.L. Gunshor M. Kobayashi
5th International Conference on II-VI Compounds招待有り1991年09月00日
国際会議口頭発表(招待・特別)
R.L. Gunshor M. Kobayashi N. Otsuka
7th International Conference on Vapor Growth and Epitaxy招待有り1991年07月00日
国際会議口頭発表(招待・特別)
M. Kobayashi D.R. Menke R.L. Gunshor
IEEE/LEOS Summer Topical Meeting on Epitaxial Materials and In-situ Processing for Optoelectronic Devices1991年07月00日
国際会議口頭発表(一般)
R.L. Gunshor M. Kobayashi N. Otsuka
Materials Research Society Meeting Symposium C招待有り1991年03月00日
国際会議口頭発表(招待・特別)
D. Li Y. Nakamura N. Otsuka J. Qiu M. Kobayashi R.L. Gunshor
1991 March Meeting of the American Physical Society1991年03月00日
国際会議口頭発表(一般)
D.R. Menke J. Han T. Stavrinides R.L. Gunshor M. Kobayashi Y. Nakamura N. Otsuka
1991 March Meeting of the American Physical Society1991年03月00日
国際会議口頭発表(一般)
D. Li Y. Nakamura N. Otsuka J. Qiu M. Kobayashi R.L. Gunshor
18th Anual Conference on Physics & Chemistry of Semiconductor Interfaces1991年01月00日
国際会議口頭発表(一般)
D.R. Menke J. Qiu R.L. Gunshor M. Kobayashi D. Li Y. Nakamura N. Otsuka
18th Anual Conference on Physics & Chemistry of Semiconductor Interfaces1991年01月00日
国際会議口頭発表(一般)
J.L. Glenn Jr. S. O M. Kobayashi R.L. Gunshor L.A. Kolodziejski D. Li N. Otsuka
the Materials Research Society Fall Meeting1990年11月00日
国際会議口頭発表(一般)
J. Qiu M. Kobayashi R.L. Gunshor Q.-D. Qian D.R. Menke D. Li N. Otsuka
6th Int'l. Conference on MBE1990年08月00日
国際会議口頭発表(一般)
J. Han S.M. Durbin R.L. Gunshor M. Kobayashi D.R. Menke Q. Fu N. Pelekanos A.V. Nurmikko Y. Nakamura N. Otsuka
6th Int'l. Conference on MBE1990年08月00日
国際会議口頭発表(一般)
D. Li Y. Nakamura N. Otsuka J. Qiu M. Kobayashi R.L. Gunshor
6th Int'l. Conference on MBE1990年08月00日
国際会議口頭発表(一般)
J. Ding N. Pelekanos Q. Fu W. Walecki A.V. Nurmikko J. Han S. Durbin M. Kobayashi R.L. Gunshor
20th Int'l Conference on the Physics of Semiconductors1990年08月00日
国際会議口頭発表(一般)
J. Ding Q. Fu N. Pelekanos W. Watecki A.V. Nurmikko S. Durbin J. Han M. Kobayashi R.L. Gunshor
20th Int'l Conference on the Physics of Semiconductors1990年08月00日
国際会議口頭発表(一般)
N. Pelekanos Q. Fu J. Ding A.V. Nurmikko M. Kobayashi S. Durbin J. Han R.L. Gunshor
20th Int'l Conference on the Physics of Semiconductors1990年08月00日
国際会議口頭発表(一般)
G. Kudlek J. G?towski S. Durbin D. Menke M. Kobayashi R.L. Gunshor
20th Int'l Conference on the Physics of Semiconductors1990年08月00日
国際会議口頭発表(一般)
S.M. Durbin J. Han M. Kobayashi R.L. Gunshor D.R. Menke Q. Fu N. Pelekanos A.V. Nurmikko
Electronic Materials Conference1990年06月00日
国際会議口頭発表(一般)
R.L. Gunshor M. Kobayashi L.A. Kolodziejski N. Otsuka Q.-D. Qian
1990 March Meeting of the American Physical Society招待有り1990年03月00日
国際会議口頭発表(招待・特別)
D. Li N. Otsuka Y. Nakamura J. Qiu M. Kobayashi R.L. Gunshor
1990 March Meeting of the American Physical Society1990年03月00日
国際会議口頭発表(一般)
G.L. Yang T. Wojtowicz M. Dobrowolska J.K. Furdyna J. Glenn M. Kobayashi L.A. Kolodziejski R.L. Gunshor
1990 March Meeting of the American Physical Society1990年03月00日
国際会議口頭発表(一般)
D. Lee Q. Fu A.V. Nurmikko R.L. Gunshor M. Kobayashi
1990 March Meeting of the American Physical Society1990年03月00日
国際会議口頭発表(一般)
N. Pelekanos Q. Fu J. Ding A.V. Nurmikko S. Durbin M. Kobayashi R.L. Gunshor
1990 March Meeting of the American Physical Society1990年03月00日
国際会議口頭発表(一般)
D.L. Mathine J. Han M. Kobayashi R.L. Gunshor D.R. Menke M. Vaziri J. Gonsalves N. Otsuka Q. Fu M. Hagerott A.V. Nurmikko
1990 March Meeting of the American Physical Society1990年03月00日
国際会議口頭発表(一般)
J. Qiu Q.D. Qian R.L. Gunshor M. Kobayashi D.R. Menke D. Li N. Otsuka
the 17th Annual Conference on Physics and Chemistry of Semiconductor Interfaces1990年01月00日
国際会議口頭発表(一般)
Q. Fu N. Pelekanos J. Ding A.V. Nurmikko S. Durbin J. Han M. Kobayashi R.L. Gunshor
International Quantum Electronics Conference1990年00月00日
国際会議口頭発表(一般)
MRS Fall Meeting '89 Symposium E "Properties of II-VI Semiconductors: Bulk Crystals Epitaxial Films Quantum Well Systems and Dilute Magnetic Systems"招待有り1989年11月00日
国際会議口頭発表(招待・特別)
D.L. Mathine J. Han M. Kobayashi R.L. Gunshor D.R. Menke M. Vaziri J. Gonsalves N. Otsuka Q. Fu M. Hagerott A.V. Nurmikko
the Materials Research Society Fall Meeting1989年11月00日
国際会議口頭発表(一般)
J. Qiu Q.-D. Qian M. Kobayashi R.L. Gunshor D.R. Menke D. Li N. Otsuka
the Materials Research Society Fall Meeting1989年11月00日
国際会議口頭発表(一般)
D. Li N. Otsuka M. Kobayashi R.L. Gunshor L.A. Kolodziejski
the Materials Research Society Fall Meeting1989年11月00日
国際会議口頭発表(一般)
R.L. Gunshor M. Kobayashi L.A. Kolodziejski A.V. Nurmikko
Fourth International Conference on II-VI Compounds招待有り1989年09月00日
国際会議口頭発表(招待・特別)
G. Kudlek N. Presser J. G?towski S.M. Durbin D. Menke M. Kobayashi R.L. Gunshor
Fourth International Conference on II-VI Compounds1989年09月00日
国際会議口頭発表(一般)
N. Pelekanos Q. Fu S. Durbin M. Kobayashi R. Gunshor A.V. Nurmikko
Fourth International Conference on II-VI Compounds1989年09月00日
国際会議口頭発表(一般)
Q. Fu N. Pelekanos A.V. Nurmikko S. Durbin J. Han Sungki O D. Menke M. Kobayashi R.L. Gunshor
EP2DS1989年09月00日
国際会議口頭発表(一般)
Q.-D. Qian J. Qiu M. Kobayashi R.L. Gunshor L.A. Kolodziejski M.R. Melloch J.A. Cooper Jr. J.M. Gonsalves N. Otsuka
16th International Symposium on GaAs and Related Compounds1989年09月00日
国際会議口頭発表(一般)
D.L. Mathine S.M. Durbin M.Kobayashi R.L. Gunshor D.R. Menke J. Gonsalves N. Otsuka Q. Fu M. Hagerott A.V. Nurmikko
Molecular Beam Epitaxy Workshop 1989年09月00日
国際会議口頭発表(一般)
R.L. Gunshor M. Kobayashi L.A. Kolodziejski A.V. Nurmikko N. Otsuka
9th International Conference on Crystal Growth (ICCG-9)招待有り1989年08月00日
国際会議口頭発表(招待・特別)
N. Otsuka D. Li J.M. Gonsalves C. Choi M. Kobayashi L.A. Kolodziejski R.L. Gunshor
Fourth International Conference on Modulated Semiconductor Structures招待有り1989年07月00日
国際会議口頭発表(招待・特別)
D.L. Mathine S.M. Durbin R.L. Gunshor M. Kobayashi D.R. Menke J. Gonsalves N. Otsuka Q. Fu M. Hagerott A.V. Nurmikko
Fourth International Conference on Modulated Semiconductor Structures 1989年07月00日
国際会議口頭発表(一般)
S.M. Durbin M. Kobayashi Q. Fu N. Pelekanos R.L. Gunshor A.V. Nurmikko
Fourth International Conference on Modulated Semiconductor Structures 1989年07月00日
国際会議口頭発表(一般)
D.L. Mathine S.M. Durbin M. Kobayashi R.L. Gunshor D.R. Menke J. Gonsalves N. Otsuka Y.R. Lee A.K. Ramdas Q. Fu M. Hagerott A.V. Nurmikko
1989 Electron Materials Conference 1989年06月00日
国際会議口頭発表(一般)
R.L. Gunshor L.A. Kolodziejski M. Kobayashi A.V. Nurmikko N. Otsuka
MRS Meeting Spring招待有り1989年04月00日
国際会議口頭発表(招待・特別)
Q.-D. Qian J. Qiu M. Kobayashi R.L. Gunshor L.A. Kolodziejski M.R. Melloch J.A. Cooper Jr. J.M. Gonsalves N. Otsuka
MRS Meeting Spring 1989年04月00日
国際会議口頭発表(一般)
R.L. Gunshor M. Kobayashi L.A. Kolodziejski A.V. Nurmikko N. Otsuka
American Vacuum Society 4th Annual Illinois Chapter Spring Meeting招待有り1989年04月00日
国際会議口頭発表(招待・特別)
Q.-D. Qian J. Qiu M. Kobayashi R.L. Gunshor L.A. Kolodziejski M. R. Melloch J. A. Cooper Jr. J. M. Gonsalves N. Otsuka
1989 March Meeting of American Physical Society1989年03月00日
国際会議口頭発表(一般)
M. Kobayashi J.L. Glenn Sungki O R.L. Gunshor L.A. Kolodziejski D. Li N. Otsuka M. Hagerott T. Heyen A.V. Nurmikko
1989 March Meeting of the American Physical Society1989年03月00日
国際会議口頭発表(一般)
Q.-D. Qian J. Qiu M. Kobayashi R.L. Gunshor M.R. Melloch J.A. Cooper Jr.
16th Physics and Chemistry of Semiconductor Interface Conference 1989年02月00日
国際会議口頭発表(一般)
J.M. Gonsalves N. Otsuka J. Qiu M. Kobayashi R.L. Gunshor L.A. Kolodziejski
Materials Research Society Meeting 1988年11月00日
国際会議口頭発表(一般)
R.L. Gunshor L.A. Kolodziejski M. Kobayashi N. Otsuka A.V. Nurmikko
SPIE-The International Society for Optical Engineering招待有り1988年11月00日
国際会議口頭発表(招待・特別)
R.L. Gunshor L.A. Kolodziejski N. Otsuka A.V. Nurmikko M. Kobayashi M.R. Melloch
Electrochemical Society Fall Meeting 招待有り1988年10月00日
国際会議口頭発表(一般)
Q.-D. Qian J. Qiu M.R. Melloch J.A. Cooper Jr. R.L. Gunshor L.A. Kolodziejski M. Kobayashi
15th International Symposium on Gallium Arsenide and Related Compounds1988年09月00日
国内会議口頭発表(一般)
J.L. Glenn Jr. Sungki O L.A. Kolodziejski R.L. Gunshor M. Kobayashi
Molecular Beam Epitaxy Workshop 1988年09月00日
国際会議口頭発表(一般)
J.L. Glenn Jr.. Sungki O L.A. Kolodziejski R.L. Gunshor M. Kobayashi J.M. Gonsalves N. Otsuka M. Hagerott T. Heyen A.V. Nurmikko
5th International Conference on Molecular Beam Epitaxy招待有り1988年08月00日
国際会議口頭発表(招待・特別)
Q.-D. Qian J. Qiu G.D. Studtmann R.L. Gunshor L.A. Kolodziejski M.R. Melloch J.A. Cooper Jr. M. Kobayashi
5th International Conference on Molecular Beam Epitaxy1988年08月00日
国内会議口頭発表(一般)
小長井誠、高橋清、小林正和、浦部和順
日本窯業協会写真展1987年10月00日
国内会議ポスター発表
道正志郎、小林正和、今井彰、小長井誠、高橋清
応用物理学会秋季大会1987年10月00日
国内会議口頭発表(一般)
M. Kobayashi S. Dosho A. Imai M. Konagai K. Takahashi
The Third International Conference on Superlattice Microstructures and Microdevices招待有り1987年07月00日
国際会議口頭発表(招待・特別)
M. Konagai M. Kobayashi R. Kimura K. Takahashi
The Third International Conference on II-VI compounds1987年07月00日
国際会議口頭発表(一般)
今井彰、小林正和、木村龍平、道正志郎、小長井誠、高橋清
応用物理学会春季大会1987年03月00日
国内会議口頭発表(一般)
R. Kimura S. Dosho A. Imai M. Kobayashi M. Konagai K. Takahashi
SPIE's International Conference on Advances in Semiconductors and Semiconductor Structures1987年03月00日
国際会議口頭発表(一般)
小長井誠、高橋清、小林正和、浦部和順
日本窯業協会写真展1986年10月00日
国内会議ポスター発表
M. Kobayashi R. Kimura M. Konagai K. Takahashi
The Fourth International Conference on Molecular Beam epitaxy (York1986年09月00日
国際会議口頭発表(一般)
小林正和、木村龍平、小長井誠、高橋清
応用物理学会秋季大会1986年09月00日
国内会議口頭発表(一般)
小林正和、三野直樹、片桐裕則、小長井誠、高橋清、浦部和順
応用物理学会春季大会1986年04月00日
国内会議口頭発表(一般)
木村龍平、三野直樹、片桐裕則、小林正和、小長井誠、高橋清
応用物理学会春季大会1986年04月00日
国内会議口頭発表(一般)
片桐裕則、小林正和、三野直樹、小長井誠、高橋清、浦部和順
電子通信学会総合全国大会1986年03月00日
国内会議口頭発表(一般)
小林正和、三野直樹、片桐裕則、木村龍平、小長井誠、高橋清
応用物理学会秋季大会1985年10月00日
国内会議口頭発表(一般)
M. Kobayashi N. Mino M. Konagai K. Takahashi
1985年06月00日
国際会議口頭発表(一般)
三野直樹、小林正和、小長井誠、高橋清
応用物理学会春季大会1985年03月00日
国内会議口頭発表(一般)
小林正和、三野直樹、小長井誠、高橋清
応用物理学会秋季大会1984年10月00日
国内会議口頭発表(一般)
小林正和、三野直樹、犬塚肇、小長井誠、高橋清
応用物理学会春季大会1984年03月00日
国内会議口頭発表(一般)
整理番号:1279
テラヘルツ帯デバイス用ZnTe薄膜の製造方法(日本)小林 正和
特願2011-188098、特開2013- 50561、特許第5926906号
整理番号:1338
埋め込み型光導波路および埋め込み型光導波路の製造方法(日本)小林 正和
特願2012-180138、特開2014- 38186
整理番号:1515
埋め込み型光導波路構造および埋め込み型光導波路装置(日本)小林 正和
特願2014-090031、特開2015-210309
研究種別:
機械化学融合法によるコアシェル型半導体ナノ粒子の創製配分額:¥2800000
研究種別:
環境変動による疲労損傷加速効果の実証と損傷回復処理配分額:¥14300000
研究種別:
マルチフェーズエピタキシ技術の構築によるワイドギャップ半導体の新規物性探査配分額:¥3000000
研究種別:
ZnSe系量子箱の自然構築法開発に関する基礎研究配分額:¥2100000
研究種別:
青色半導体レーザ作製のための複合光励起有機金属気相成長技術の開発研究配分額:¥1200000
研究種別:
光プローブによる結晶成長の原子・分子レベルの新しいその場観察法の研究-表面光干渉法-配分額:¥6300000
2013年度
研究成果概要:再生可能なエネルギー源に関する研究開発が現在盛んに行われている。中でも太陽電池に関する研究は実用化に近付いており、社会においてニーズの高い重要な研究テーマである。太陽電池デバイスの中でも単結晶Si太陽電池は、他の太陽電池に比べて寿...再生可能なエネルギー源に関する研究開発が現在盛んに行われている。中でも太陽電池に関する研究は実用化に近付いており、社会においてニーズの高い重要な研究テーマである。太陽電池デバイスの中でも単結晶Si太陽電池は、他の太陽電池に比べて寿命が長く太陽光の変換効率が高い。しかし、Si太陽電池の変換効率は約20%で理論限界値に近づいている。シリコン太陽電池の課題の一つに太陽光の高エネルギー成分である短波長成分を有効活用出来ていないことが挙げられる。本研究では、この短波長成分を蛍光体の利用により長波長光へ変換し太陽光エネルギーの利用効率を改善することについて注目した。特に波長変換材料には、蛍光効率の高い赤色蛍光体Ba2ZnS3:Mn (BZS)に注目した。この赤色蛍光体BZSをナノ粒子にし単結晶Si太陽電池の前面に配置することで、太陽光の長波長光を損失無くそのまま透過させ短波長光だけを変換することが期待出来る。従来の研究では、BZSを物理的粉砕法によりナノ粒子にし、スピンコート法を用いることで赤色蛍光ナノ粒子塗布膜を作製してきた。しかしこの赤色蛍光ナノ粒子塗布膜は、粉砕されたままのBZSナノ粒子の発光強度が劣化していることが原因で光学的特性が十分なものとは考えにくかった。そこで粉砕されたままのBZSナノ粒子の発光強度回復について検討を行った。粉砕によるダメージは真空中のアニール処理により回復させることに注目した。 アニール温度を1100℃まで上げるにつれ試料のX線回折信号測定の信号強度が強くなっていることから、BZSの結晶性が回復していることが確認出来た。また、1000,1100℃でアニール処理したBZSは従来のアニール処理のBZSと比較すると、131の回折強度が2.5倍になった。このことからBZSの結晶性が従来よりも良くなっていることが明らかになった。今回用いたアニール条件の範囲ではアニールを行ってもスペクトル形状への影響は確認されなかった。PLスペクトルのピーク値は630nmであり、半値幅は全て同じであった。また、従来のZnSを隣接しないアニール処理を施したBZSと比較して、蛍光強度が約8倍になった。アニール温度を1000℃まで上昇させると、それに伴ってPL強度は単調に増加した。そして1000℃以上ではでPL 強度の変化は、ほとんど無くなっていることも明らかになった。アニール温度が高温になるに従い、強い蛍光が観測されたのは高温のアニール処理により粒子表面に存在していた欠陥が回復されたためであると考えられる。
2016年度
研究成果概要:Te系I-III-VI2族カルコパイライト材料のなかでもAgGaTe2は室温でのバンドギャップが1.3eVと太陽電池応用に適している。しかし、ソースにAg2TeとGa2Te3の混合粉末を用いて、Ag2Te中間層上に堆積させているた...Te系I-III-VI2族カルコパイライト材料のなかでもAgGaTe2は室温でのバンドギャップが1.3eVと太陽電池応用に適している。しかし、ソースにAg2TeとGa2Te3の混合粉末を用いて、Ag2Te中間層上に堆積させているため、ストイキオメトリ制御が難しく、Ag2TeやAgGa5Te8といった副生成物が生成されやすい。そこで本研究ではそれぞれの膜厚をコントロールすることで組成制御が比較的容易に行えるGa2Te3/Ag2Teという2層構造に着目し、AgGaTe2薄膜の形成をGa2Te3/Ag2Teを連続して堆積させることにより試みた。Ag2Te層上にGa2Te3層を堆積させた膜は、AgGaTe2由来のピークのみが表れた。このことよりGa2Te3堆積中にGa2Te3の堆積とGa2Te3/Ag2Te層の再結晶化が同時に起こり、結果としてAgGaTe2膜が形成されていることが明らかとなった。
2017年度
研究成果概要:2段階近接昇華法を用いることで高品質テルル系カルコパイライト薄膜の作製が可能になってきた。AgGaTe2の成果をもとに、CuGaTe2の2段階近接昇華法が応用可能かどうかについて検討を行った。そこで中間層材料としてCu2Teに着目...2段階近接昇華法を用いることで高品質テルル系カルコパイライト薄膜の作製が可能になってきた。AgGaTe2の成果をもとに、CuGaTe2の2段階近接昇華法が応用可能かどうかについて検討を行った。そこで中間層材料としてCu2Teに着目した。シリコン基板上にCu2Te中間層を作製したところ、面内密度の改善が進み、比較的高密でのCu2Te粒状構造が確認された。さらにMo上にCu2Teを作製したところ、ほぼ膜状に分布した構造も作製できることが明らかになった。さらにその上にCuGaTe2を作製したところ、平坦性の高い薄膜状の結晶が得られるようになった。X線回折法を用いて結晶性を評価したところ、CuGaTe2が得られていることが明らかになった。
2018年度
研究成果概要:近接昇華法を用いてMo/quartz基板上にソース温度を変化させてCu2Te膜と二段階目のCuGaTe2膜の作製を行い、それぞれの膜厚に与える影響を探査した。また、1段階目のCu2Te中間層の膜厚を一定とし、2段階目のCu2Teと...近接昇華法を用いてMo/quartz基板上にソース温度を変化させてCu2Te膜と二段階目のCuGaTe2膜の作製を行い、それぞれの膜厚に与える影響を探査した。また、1段階目のCu2Te中間層の膜厚を一定とし、2段階目のCu2TeとGa2Te3の混合粉末原料の重量を変化させることでCu-Ga-Te膜の形成相にどのような影響を与えるか探査した。ソース温度を上げて作製することにより、太陽電池応用に向けて必要な膜厚1μmのCuGaTe2の作製に成功した。また、二段階目のCu2TeとGa2Te3の混合粉末原料の重量を変化させることで堆積物のGa2Te3のモル分率が変化し、Cu-Ga-Te膜の形成相の種類や量が変化することが明らかとなった。
2019年度
研究成果概要:m面サファイア基板上に分子線エピタキシー法で高品質ZnTe薄膜の作製に取り組んできた。1200~1500℃の高温で基板を大気中に放置することでナノファセットと呼ばれるr面とS面の周期構造が形成可能なことが明らかになった。r面とS面...m面サファイア基板上に分子線エピタキシー法で高品質ZnTe薄膜の作製に取り組んできた。1200~1500℃の高温で基板を大気中に放置することでナノファセットと呼ばれるr面とS面の周期構造が形成可能なことが明らかになった。r面とS面で核形成から成長初期の状態までの間が大きく異なること、特に成長温度によって大きな影響を受けることを明らかにした。特に温度が高くなるにつれてr面上に堆積が減少してくることを明らかにした。さらに成長初期に高温で原料の交互供給をすることが高品質の薄膜作製に重要なことであると明らかにした。実際に成長初期核をS面上に選択的に形成することが可能になったことで極めて配向性の高いZnTe薄膜が得られた。
2000年度
研究成果概要: ワイドギャップII-VI族化合物半導体は禁制帯幅が広いことから可視光領域の発光・受光素子用材料として注目されている。特に近年はその量子ドット構造に関しては特徴的な発光特性が期待できることより注目されている。量子ドットを電子素子と... ワイドギャップII-VI族化合物半導体は禁制帯幅が広いことから可視光領域の発光・受光素子用材料として注目されている。特に近年はその量子ドット構造に関しては特徴的な発光特性が期待できることより注目されている。量子ドットを電子素子として作りこむことを想定するとエピタキシャル膜中に量子ドットを作りこむことが課題となってくる。我々は特に基板の中でも、結晶性がよく、広く普及されつつあるZnTe基板に注目し、その基板上に量子ドットを形成することを意図した。 基板が普及しつつあるとはいうものの、まだ、エピタキシャル成長用の基板表面処理技術が確立していないことは、量子ドットの成長に対して大きな問題点となっている。そこで、さまざまな化学エッチャントにより基板表面を処理し、エッチングの表面平坦性・表面ストイキオメトリ・表面酸化膜(保護膜)の厚みなどについて検討を行った。 基板の化学処理方法としては、通常の化合物半導体で広く使われている硫酸系の試薬、HBr系試薬、クエン酸系試薬などを用いた。まず、表面平坦性の観点では硫酸系の試薬を使った場合には鏡面が得られなくなるほど悪化してしまうため、適当でないとの結論に達した。その他の試薬では、薬品濃度が表面平坦性の再現性に影響を与えるが、条件を十分に設定することにより、エピタキシャル膜の成長に利用できる程度の表面平坦性が得られることがAFM観察より明らかになった。また、HBr系の試薬を用いた場合は表面酸化膜の厚みが薄いこと、クエン酸系の試薬を用いた場合には表面がTeリッチになることなどがXPS測定やAES測定より明らかになった。 今後は表面平坦性がエピタキシャル成長としても対応可能であると考えられる試薬を用いて表面処理を行い、その表面上に実際にZnTe層や量子ドット層等の成長を試み、どの処理方法が量子ドット形成に最適であるかを明らかにする予定である。
2002年度
研究成果概要: 近年紫外線に関する諸問題が注目されており,紫外線センサの研究が活発に進められている.GaN系材料ではUVAを感知することは困難なため,Ⅱ-Ⅵ族の4元混晶が注目されている.ZnMgCdSは(100)GaAs基板に格子整合し,かつU... 近年紫外線に関する諸問題が注目されており,紫外線センサの研究が活発に進められている.GaN系材料ではUVAを感知することは困難なため,Ⅱ-Ⅵ族の4元混晶が注目されている.ZnMgCdSは(100)GaAs基板に格子整合し,かつUVAのエネルギーに対応する3eVをMg濃度10%で実現できる.また,Ⅱ-Ⅱ-Ⅱ-Ⅵ系の材料であることから組成制御もしやすいと考えられる.そこで,ZnMgCdSをMBEにより成長し,UVAセンサとしての適応性について検討した. ZnMgCdSをZn,Mg及びCdS化合物を用いて(100)GaAs基板上に成長させた.条件は基板温度150-230℃,BEP比(Zn+Mg)/CdS=0.03-0.35の間で変化させた.基板温度150℃でBEP比=0.03の場合,CdがZn,Mgに置換されなかった.次に220℃,BEP比=0.068ではCdがZnとMgに対して1:1の割合で置換されていた.その結果,GaAsにほぼ格子整合し,室温でのバンド端が3eV付近のZnMgCdSを成長させることができた.さらに,230℃でBEP比=0.35に上げるとCdがほぼ100%置換されていた.これらのことは従来報告されているZnCdSのSの被服率によるZn,Cd付着率の関係と一致していた.10KでのPLスペクトル測定の結果より、Zn,Mgの含有量が増えるに従ってエネルギーギャップが増大していることが明らかになった.但し組成比が面内で分布しているためかピークは比較的ブロードなものになった.また,Au電極を蒸着することによりMSM構造のセンサを作製した.その結果,UVA以上のエネルギーをもつ光にのみ選択的に反応し,伝導率が変化していることが明らかになった。
2015年度
研究成果概要:電気光学効果を利用した高感度テラヘルツ波検知器の実現に向け、透明基板であるサファイア上に面方位が制御された状態の高品質ZnTe薄膜を作製することを目指している。サファイアS面やR面を基板にもちい、成長薄膜との界面の方位関係を調べた...電気光学効果を利用した高感度テラヘルツ波検知器の実現に向け、透明基板であるサファイア上に面方位が制御された状態の高品質ZnTe薄膜を作製することを目指している。サファイアS面やR面を基板にもちい、成長薄膜との界面の方位関係を調べた。S面上に作製されたZnTeをX線回折法、特に極点図法を用いて解析した。S面基板上に作製する場合にはサファイアC面が大きな影響を与えているが、R面上には異なった形で結晶成長が行われた。ただし、結晶性に関してはS面上に作製されたZnTeより高品質であることが明らかになった。界面を詳細に検討し、C面の情報を引継ぐと同時に表面の原子配置も大きな影響を及ぼしていることが明らかになった。
2004年度
研究成果概要:GaAsに格子整合し、かつ室温でのEgを3eVに制御可能なZnMgCdS系材料に注目し、紫外線センサへの適応性を検討した。4元混晶に限定することなく、センサ特性改善のため超格子構造のZn0.6Cd0.4S/Mg0.8Cd0.2Sを...GaAsに格子整合し、かつ室温でのEgを3eVに制御可能なZnMgCdS系材料に注目し、紫外線センサへの適応性を検討した。4元混晶に限定することなく、センサ特性改善のため超格子構造のZn0.6Cd0.4S/Mg0.8Cd0.2Sを作製し、紫外線センサへの適応性の検討を行なったところZnMgCdS材料の場合と同様に紫外光のみ選択的に感度のあるセンサを作製することができた。しかし、結晶成長とともに3次元成長が起こり結晶性が悪化し、センサ特性に影響が出るという問題が明らかになった。そこで、従来とはことなり、GaAs基板上に作製する代わりにエピタキシャル成長させた平坦なGaAs上にZnCdS/MgCdSを作製し、結晶性の改善とセンサの分光感度特性の改善を試みた。(100)GaAsエピタキシャル膜上にZnSeバッファ層成長後、ZnMgS/CdMgSをZn、Mg及びCdS化合物を用いて成長させた。組成はZn 0.4Cd 0.6S/Mg 0.8Cd 0.2S付近に設定し、層厚は9 –60Å/8 –20Åで作製した。RHEED観察においてGaAs基板上にZnSeバッファ層を成長した場合は成長開始直後からスポットになった。それに対しGaAsエピタキシャル膜上の場合は成長開始直後からストリークが見られ、超格子600nm成長後でもGaAsエピタキシャル膜上に成長したものはストリークが保たれていた。これらのことはGaAsとの界面の平坦性が改善されたことにより超格子の結晶性を改善できたためと考えられる。PL・反射スペクトルから2.95eV付近にEgに対応した強い発光が得られた。本超格子を用いて光導電素子のUVAセンサを作製したところ、従来の構造に比べカットオフ波長付近での感度特性が改善された。
2017年度
研究成果概要:2段階近接昇華法を用いることで高品質テルル系カルコパイライト薄膜の作製が可能になってきた。様々な条件によってシリコン基板上に作製されたAgGaTe2の光学的特性を極低温フォトルミネッセンス(PL)法によって評価した。PLスペクトル...2段階近接昇華法を用いることで高品質テルル系カルコパイライト薄膜の作製が可能になってきた。様々な条件によってシリコン基板上に作製されたAgGaTe2の光学的特性を極低温フォトルミネッセンス(PL)法によって評価した。PLスペクトルから1.02 eV付近と1.32 eV付近に2つのピークが観測された。詳細解析の結果1.32 eV付近の発光は自由励起子由来の発光であった。状態図をもとに薄膜内の結晶について検討を行ったところ、AgGa5Te8を含むAgGaTe2薄膜においては自由励起子由来の発光がつよく確認されるがAg2Teを含むと自由励起子由来の発光が消光することが明らかになった。
2010年04月-2010年09月
機関: アリゾナ大学(アメリカ)、カンタベリ大学(ニュージーランド)
科目名 | 開講学部・研究科 | 開講年度 | 学期 |
---|---|---|---|
電気・情報生命工学フロンティア | 先進理工学部 | 2020 | 春学期 |
電気・情報生命工学フロンティア 【前年度成績S評価者用】 | 先進理工学部 | 2020 | 春学期 |
電気・情報生命工学実験A | 先進理工学部 | 2020 | 秋学期 |
電気・情報生命工学実験A 【前年度成績S評価者用】 | 先進理工学部 | 2020 | 秋学期 |
プロジェクト研究A | 先進理工学部 | 2020 | 春学期 |
プロジェクト研究A 【前年度成績S評価者用】 | 先進理工学部 | 2020 | 春学期 |
プロジェクト研究B | 先進理工学部 | 2020 | 秋学期 |
プロジェクト研究B 【前年度成績S評価者用】 | 先進理工学部 | 2020 | 秋学期 |
卒業研究A | 先進理工学部 | 2020 | 春学期 |
卒業研究A 【前年度成績S評価者用】 | 先進理工学部 | 2020 | 春学期 |
卒業研究B | 先進理工学部 | 2020 | 秋学期 |
卒業研究B (春学期) | 先進理工学部 | 2020 | 春学期 |
卒業研究B 【前年度成績S評価者用】 | 先進理工学部 | 2020 | 秋学期 |
卒業研究B (春学期) 【前年度成績S評価者用】 | 先進理工学部 | 2020 | 春学期 |
電子回路B | 先進理工学部 | 2020 | 春学期 |
電子デバイス | 先進理工学部 | 2020 | 春学期 |
Graduation Thesis A | 先進理工学部 | 2020 | 秋学期 |
Graduation Thesis B | 先進理工学部 | 2020 | 春学期 |
修士論文(電生) | 大学院先進理工学研究科 | 2020 | 通年 |
Research on Electronic and Photonic Materials | 大学院先進理工学研究科 | 2020 | 通年 |
電子・光子材料学研究 | 大学院先進理工学研究科 | 2020 | 通年 |
電子・光子材料学特論 | 大学院先進理工学研究科 | 2020 | 秋学期 |
Advanced Seminar A | 大学院先進理工学研究科 | 2020 | 春学期 |
特別演習A | 大学院先進理工学研究科 | 2020 | 春学期 |
Advanced Seminar B | 大学院先進理工学研究科 | 2020 | 秋学期 |
特別演習B | 大学院先進理工学研究科 | 2020 | 秋学期 |
Seminar on Electronic and Photonic Materials A | 大学院先進理工学研究科 | 2020 | 春学期 |
電子・光子材料学演習A | 大学院先進理工学研究科 | 2020 | 春学期 |
Seminar on Electronic and Photonic Materials B | 大学院先進理工学研究科 | 2020 | 秋学期 |
電子・光子材料学演習B | 大学院先進理工学研究科 | 2020 | 秋学期 |
Seminar on Electronic and Photonic Materials C | 大学院先進理工学研究科 | 2020 | 春学期 |
電子・光子材料学演習C | 大学院先進理工学研究科 | 2020 | 春学期 |
Seminar on Electronic and Photonic Materials D | 大学院先進理工学研究科 | 2020 | 秋学期 |
電子・光子材料学演習D | 大学院先進理工学研究科 | 2020 | 秋学期 |
Master's Thesis (Department of Electrical Engineering and Bioscience) | 大学院先進理工学研究科 | 2020 | 通年 |
電子・光子材料学研究 | 大学院先進理工学研究科 | 2020 | 通年 |