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Affiliation |
Engineering educational research section Semiconductor Science and Applied Physics Program |
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Associate Professor |
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SUZUKI Hidetoshi
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Papers 【 display / non-display 】
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T. Harada,S. Harada, H. Suzuki, S. Endo, A. Ogura, M. Imaizumi, T. Ikari, A. Fukuyama
Journal of Physics D: Applied Physics 58 ( 11 ) 2025.3
Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Physics D: Applied Physics
To reduce fluctuations in the performance of lattice-mismatched solar cells within a wafer, it is necessary to characterize and quantify the effect of misfit dislocations, caused by strain relaxation, on the performance of a solar cell. To this end, the relationship between the preferential glide planes (GPs) and the carrier generation-recombination process in InGaAs solar cells with low (LowV) and high (HighV) open-circuit voltages has been investigated in this study. The GPs of the β dislocations in the HighV cells were uniformly controlled in the wafer plane. However, the LowV cells contained a mixture of two in-plane regions, in which the GPs of the β dislocations were controlled by the surface atomic steps during their growth on a vicinal substrate (LowV-sub region) or by the InGaP ordering effect (LowV-ord region). The results of the microwave photoconductivity decay method and our newly-developed laser heterodyne photothermal displacement method suggested that the photoexcited carrier concentration was low in the LowV-ord region. A photoluminescence measurement as a function of temperature further revealed that indium fluctuations occurred due to the presence of the GPs of the β dislocation. The LowV cells exhibited high indium composition and reduced bandgap. Thus, a small photoexcited carrier concentration and reduced bandgap energy decreased the difference between the quasi-Fermi levels of electrons and holes, resulting in a small VOC. The photovoltaic performance could be determined by the density of the threading dislocations and the corresponding fluctuations in the indium composition owing to the different GPs of the β dislocations.
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M. Kawano, T. Haraguchi, H. Suzuki
Journal of Crystal Growth 649 2025.1
Authorship：Last author, Corresponding author Language：English Publishing type：Research paper (scientific journal) Publisher：Journal of Crystal Growth
The effects of nitrogen (N) distribution on the electrical properties of GaAsN films were evaluated by intentionally changing the N distribution using atomic layer epitaxy (ALE) and post-annealing. The N distribution was controlled in the growth direction by growing superlattice (SL) thin films repeatedly growing 1 GaAsN layer and 0, 3, and 5 layers of GaAs by ALE. These films were referred to as (1:0), (1:3), and (1:5), respectively. To change the N distribution in the same thin film, N atoms were diffused by post-annealing. Changes in N distribution were evaluated by X-ray diffraction as changes in GaAsN superstructure. N atoms diffused from GaAsN layers to the adjacent layers in (1:3) films annealed above 750 °C, while they remained stable in those of (1:5) films annealed at temperatures up to 850 °C. The carrier mobility of both films increased monotonically with the annealing temperature. The concentration of ionized scattering centers decreased significantly in films annealed at 650 °C (independent of their N distributions) owing to the elimination of donor-type defects by annealing. Contrarily, the concentrations of N-induced scattering centers in (1:5) films annealed below 900 °C were similar, while those in (1:3) films annealed above 750 °C decreased significantly, in agreement with the N-atom diffusion behavior of GaAsN layers. Thus, N-distribution homogenization can be related to the reduction of N-induced scattering centers.
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Harada Shogo, Harada Tomoki, Suzuki Hidetoshi, Ogura Akio, Ikari Tetsuo, Fukuyama Atsuhiko
53 57 - 64 2024.10
Language：Japanese Publishing type：Research paper (bulletin of university, research institution) Publisher：Faculty of Engineering, University of Miyazaki
DOI： 10.34481/0002000816
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逆格子マッピング測定を用いた、格子不整合InGaAs太陽電池の転位滑り面の面内分布異方性の観察
鈴木 秀俊
九州シンクロトロン光研究センター利用報告書2023年度 2024.10
Authorship：Lead author Language：Japanese Publishing type：Research paper (bulletin of university, research institution)
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Ogura A., Nogawa S., Kawano M., Minematsu R., Suzuki H.
Applied Physics Express 14 011001 2020.12
Language：English Publishing type：Research paper (scientific journal)
By using synchrotron X-ray diffraction, we investigated the in-plane distribution of preferential glide planes in a metamorphic InGaAs solar cell with a relatively low open-circuit voltage (Voc) compared to other cells fabricated on the same wafer. The reciprocal-space maps revealed that the low-Voc cell contains several domains with different preferential glide planes of β dislocations. Since fluctuations of the average β-glide plane have not been observed for high-Voc cells, the observed inhomogeneous distribution should be related to the Voc degradation. Understanding preferential glide-plane changes within a cell can help to improve the uniformity of cell properties over the whole wafer.
Books 【 display / non-display 】
MISC 【 display / non-display 】
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Sasaki T., Suzuki H., Sai A., Takahasi M., Fujikawa S., Kamiya I., Ohshita Y., Yamaguchi M.
Journal of Crystal Growth 387 2014.2
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (bulletin of university, research institution) Publisher：Journal of Crystal Growth
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Ohshita Y., Suzuki H., Kojima N., Tanaka T., Honda T., Inagaki M., Yamaguchi M.
Journal of Crystal Growth 374 2013.7
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (bulletin of university, research institution) Publisher：Journal of Crystal Growth
© 2013 Elsevier B.V. The affiliation of the second author should be corrected. The correct affiliation is as follows. Interdisciplinary Research Organization, University of Miyazaki, 1-1 Gakuen Kibana-dai Nishi, Miyazaki 889-2192, Japan.
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Sasaki T., Suzuki H., Takahasi M., Ohshita Y., Kamiya I., Yamaguchi M.
Journal of Applied Physics 113 ( 19 ) 2013.5
Language：Japanese Publishing type：Article, review, commentary, editorial, etc. (bulletin of university, research institution) Publisher：Journal of Applied Physics
DOI： 10.1063/1.4804236
Presentations 【 display / non-display 】
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有機金属気相成長法によって作製されたInAs/GaAsSb 超格子のAs組成比による発光の変化
奥田 大晴、荒井 昌和、藤澤 剛、鈴木 秀俊、前田 幸治
第72回応用物理学会春季学術講演会 2025.3.16
Event date： 2025.3.14 - 2025.3.17
Language：Japanese Presentation type：Oral presentation (general)
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逆積み式InGaAs太陽電池における成長層傾斜不均一の発生位置の評価
栗崎皋成、鈴木秀俊、小倉暁雄、今泉充
2024年応用物理学会九州支部学術講演会 2024.12.8
Event date： 2024.12.7 - 2024.12.8
Language：Japanese Presentation type：Oral presentation (general)
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Growth and evaluation of GaAsN films with different N distribution grown by atomic layer epitaxy International conference
Hayato Koto, Masahiro Kawano, Hidetoshi Suzuki
35th International Photovoltaic Sicence and Engineering Conference 2024.11.14
Event date： 2024.11.10 - 2024.11.15
Language：English Presentation type：Poster presentation
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Effects of Intentionally changed nitrogen distribution on nitrogen localized level in GaAsN thin films International conference
Kyosuke Yamashita, Tomoki Harada, Masahiro Kawano, Hidetoshi Suzuki, Tetsuo Ikari, Atsuhiko Fukuyama
2024 International Conference on Solid State Devices and Materials 2024.9.3
Event date： 2024.9.1 - 2024.9.4
Language：English Presentation type：Poster presentation
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GaAs基板上InGaAsバッファ層を用いたType-Ⅱ量子井戸の成長と評価
高島 陸人、本部 好記、臼井 一旗、國武 幸一郎、鈴木 秀俊、荒井 昌和
第71回応用物理学会春季学術講演会 2024.3.22
Event date： 2024.3.22 - 2024.3.25
Language：Japanese Presentation type：Oral presentation (general)
Awards 【 display / non-display 】
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応用物理学会講演奨励賞
2020.3 日本応用物理学会 成長温度の異なるGaAsSb/GaAs(001)の格子緩和異方性評価
久保 幸士朗,野川 翔太，河野 将大，佐々木 拓生，高橋 正光，鈴木 秀俊
Award type：Award from Japanese society, conference, symposium, etc. Country：Japan
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PVSEC poster aword
2016.10 PVSEC organizing committee Nucleation layer grown by atomic layer deposition for selective-area growth of GaAs on patterned Si substrates by using chemical beam epitaxy
Yu-Cian Wang, Hidetoshi Suzuki, Yuki Yokoyama, Tetsuo Ikari, Atsuhiko Fukuyama, Nobuaki Kojima, Yoshio Ohshita,Masafumi Yamaguchi
Award type：Award from international society, conference, symposium, etc. Country：Singapore
Grant-in-Aid for Scientific Research 【 display / non-display 】
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格子不整合エピタキシャル膜における転位異方性が異なる「結晶粒」発生起源の解明
Grant number：23K04603 2023.04 - 2026.03
独立行政法人日本学術振興会 科学研究費基金 基盤研究(C)
Authorship：Principal investigator
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原子層エピタキシー法を用いた希薄窒化物半導体中の窒素分布三次元制御
Grant number：20K05346 2020.04 - 2023.03
独立行政法人日本学術振興会 科学研究費補助金 基盤研究(C)
Authorship：Principal investigator
希薄窒化物半導体は、SiやGeに格子整合可能でバンドギャップエネルギーを広範囲に制御可能であり、格子整合させた多接合太陽電池や光電子集積回路に期待されている。しかし、窒素(N)原子導入による電気特性の劣化が問題となっている。その原因として膜中のN分布の不均一性が考えられているが、直接N分布を観察することが困難なため、本質的な理解には至っていない。本研究では、希薄窒化物半導体であるGaAsN膜中において、(i)N原子の空間分布を三次元で制御したGaAsN薄膜の作製、(ii)実際のN分布の評価、(iii)N原子の空間分布がN局在準位(EN)および電気特性に与える影響の解明、の３点が目的である。これまでにN分布制御は試みられているが、成長方向への制御のみであった。本研究により、GaAsN膜中のN原子の三次元的な空間分布とENおよび電気特性との関係が明らかになれば、GaAsNも含めた希薄窒化物半導体材料全ての高品質化に指針を与える。
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希土類の価数変化を利用した新しいタイプの 高分解能X線検出材料の開発
Grant number：16K05955 2016.04 - 2019.03
科学研究費補助金 基盤研究(C)
Authorship：Coinvestigator(s)
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原子層エピタキシー法を用いた希薄化物半導体の窒素空間分布制御
Grant number：20K05346 2016.04 - 2019.03
科学研究費補助金 若手研究(B)
Authorship：Principal investigator
本研究では、希薄窒化物半導体であるGaAsN膜中の窒素(N)原子の空間分布と、エネルギーバンド中にN原子が作るN局在準位(EN)との関係を明らかにし、ENの変化が電気特性に与える影響を知る事が目的である。申請者等はこれまでにGaAsN膜のENの評価を行い、N組成で一意に決まらずN原子の空間分布および電気的特性にも大きく関わっている可能性を見いだしているが、これらの具体的な相関は明らかになっていない。本研究により、GaAsN膜中のN原子の空間分布と電気特性との関係が明らかになれば、本材料も含めた希薄窒化物半導体材料全ての電気的特性を飛躍的に向上させるブレイクスルーとなる事が期待される。
Available Technology 【 display / non-display 】
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多接合太陽電池用新材料の開発
III-V 族化合物半導体の結晶成長
放射光を用いた半導体結晶の構造評価Home Page： ・宮崎大学工学部応用物理工学プログラムHP
Related fields where technical consultation is available：・各種物質の同定、結晶構造、欠陥評価、(X 線回折、電子回折)。
・半導体材料の構造・電気特性評価
・放射光施設の高輝度 X 線を利用した構造評価、その場測定Message：・物質の構造評価、特に X 線や電子線を用いた手法を得意としています。
・これらのことで迷うことがありましたら、是非ご相談ください。