OHDAIRA, Keisuke Professor
Materials Science, Sustainable Innovation
◆Degrees
Ph.D. from The University of Tokyo 東京大学
◆Professional Experience
2018 - : Japan Advanced Institute of Science and Technology , 先端科学技術研究科マテリアルサイエンス系 , 教授
2016 - 2018 : Japan Advanced Institute of Science and Technology , 先端科学技術研究科マテリアルサイエンス系 , 准教授
2012 - 2016 : Japan Advanced Institute of Science and Technology , グリーンデバイス研究センター , 准教授
2009 - 2013 : Japan Science and Technology Agency , さきがけ研究 , 兼任研究者
2006 - 2011 : Japan Advanced Institute of Science and Technology , マテリアルサイエンス研究科 , 助教
2005 - 2006 : Japan Advanced Institute of Science and Technology , 材料科学研究科 , 助教
2004 - 2005 : Tohoku University , Institute for Materials Research , 博士研究員
2000 - 2004 : The University of Tokyo , The Graduate School of Engineering Department of Applied Physics , Doctoral course
1998 - 2000 : The University of Tokyo , The Graduate School of Engineering Department of Applied Physics , Master's Course
◆Specialties
Material fabrication and microstructure control, Crystal engineering, Applied materials
◆Research Keywords
Catalytic chemical vapor deposition, 太陽電池, 結晶化, 簿膜, 多結晶シリコン, フラッシュランプアニール, スパッタリング, 熱処理, 高温加圧加工, 半導体結晶, X線用レンズ
◆Research Interests
Formation of high-quality poly-Si films by flash lamp annealing and their application to high-efficiency solar cells
We investigate on formation of high-quality poly-Si on glass substrates by flash lamp annealing, with millisecond duration, of Cat-CVD a-Si films and fabrication of solar cells using the poly-Si films.
Application of Cat-CVD to the fabrication process of c-Si solar cells
Cat-CVD (catalytic chemical vapor deposition), in which gas molecules are decomposed on heated catalyzing wire by catarytic reaction, can deposit high-quality passivation films to reduce the recombination of photo-generated carriers on crystalline Si surface. We develop high-quality Cat-CVD passivation films for crystalline Si solar cells. We also investigate a novel doping method using a Cat-CVD system.
Potential-induced degradation for n-type crystalline silicon photovoltaic modules
The performance degradation of photovoltaic modules originating from a large voltage between an Al frame and cells (potential-induced degradation: PID) has been a significant problem in large-scale PV power plants. We investigate the mechanism of PID and its suppression particularly for n-type c-Si PV modules, which have higher performances than p-type ones and are thus expected to be widely utilized in the future.

■Publications

◆Published Papers
Delay of the potential-induced degradation of n-type crystalline silicon photovoltaic modules by the prior application of reverse bias
Deqin Wu, Huynh Thi Cam Tu, Keisuke OHDAIRA
Japanese Journal of Applied Physics, 63, 2, 02SP06-02SP06, 2024
Long term stability of low temperature deposited Cat-CVD SiN x thin film against damp-heat stress
Huynh Thi Cam Tu, Keisuke OHDAIRA
Japanese Journal of Applied Physics, 63, 1, 01SP25-01SP25, 2024
Ultrathin Al-doped SiO x passivating hole-selective contacts formed by a simple wet process
Hiroki Nakajima, Huynh Thi Cam Tu, Keisuke Ohdaira
Japanese Journal of Applied Physics, 62, SK, SK1040-SK1040, 2023
Potential-induced degradation of encapsulant-less p-type crystalline Si photovoltaic modules
Shuntaro Shimpo, Huynh Thi Cam Tu, Keisuke Ohdaira
Japanese Journal of Applied Physics, 62, SK, SK1039-SK1039, 2023
Second-stage potential-induced degradation of n-type front-emitter crystalline silicon photovoltaic modules and its recovery
Keisuke Ohdaira, Yutaka Komatsu, Seira Yamaguchi, Atsushi Masuda
Japanese Journal of Applied Physics, 62, SK, SK1033-SK1033, 2023
◆Misc
Silicon heterojunction solar cells with a counter-doped n-a-Si film treated by flash lamp annealing
Y. Liu, H. T. C. Tu, N. Yamaguchi, K. Ohdaira
Extended Abstract of the 2021 International Conference on Solid State Devices and Materials (SSDM 2021), -, 2021
Effect of temperature and pre-annealing on the potential-induced degradation of silicon heterojunction photovoltaic modules
J. Xu, H. T. C. Tu, A. Masuda, K. Ohdaira
Extended Abstract of the 2021 International Conference on Solid State Devices and Materials (SSDM 2021), -, 2021
Hydrogenation on tunnel nitride passivated contacts by catalytically generated atomic hydrogen
Y. Wen, H. T. C. Tu, and K. Ohdaira
Extended Abstract of the 2021 International Conference on Solid State Devices and Materials (SSDM 2021),, -, 2021
Influence of UV light on the increase of SiNx conductivity toward elucidation of potential induced degradation mechanism
Dong Chung Nguyen, Yasuaki Ishikawa, Cong Thanh Nguyen, Keisuke Ohdaira, Atsushi Masuda, Yukiharu Uraoka
Proceedings of 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC), 317-320, 2020
Influence of light illumination on the potential-induced degradation of n-type interdigitated back-contact crystalline Si photovoltaic modules
Y. Xu, A. Masuda, K. Ohdaira
Extended Abstract of the 2020 International Conference on Solid State Devices and Materials (SSDM 2020), -, 2020
◆Books
The Work Behind the Scenes for the First Ever Online Event of SSDM2020
単著, AAPPS Bulletin 32, Article number: 4, 2022
ホッとひといき SSDM2020初のオンライン開催の舞台裏
応用物理 第90巻, 第4号, 2021
ホッとひといき 支部学術講演会を知ろう
応用物理 第89巻, 第6号, 2020
今月のトピックス 展示ブースにお邪魔しました
その他, 応用物理 第88巻, 第9号, 2019
研究機関トップからのメッセージ 夢に向かって、目の前の山を登り切る
その他, 応用物理 第88巻, 第8号, 2019
◆Conference Activities & Talks
ベイズ最適化を適用したCat-CVD i-a-Siおよびn-a-Siの堆積条件探索
第14回半導体・デバイスフォーラム(SMDF2023)(九州工業大学), 2023
3種類の回帰モデルを駆使したベイズ最適化によるCat-CVD i-a-Siの堆積条件検討
第52回結晶成長国内会議(JCCG-52)(ウィンクあいち), 2023
太陽電池モジュールの劣化機構と新概念構造の開発
応用物理学会 応用電子物性分科会 研究例会「太陽電池モジュールの基礎と将来展開」(オンライン), 2023
Effectiveness of Al-induced charged oxide inversion layer on pyramidal textured Si surfaces
The 34th International Photovoltaic Science and Engineering Conference (PVSEC-34)(Shenzhen World Exhibition & Convention Center), 2023
Effect of cover glass morphology on the potential-induced degradation of n-type front-emitter crystalline silicon photovoltaic modules
The 34th International Photovoltaic Science and Engineering Conference (PVSEC-34)(Shenzhen World Exhibition & Convention Center), 2023

■Teaching Experience

Mathematics for Condensed Matter Science and Technology, Advanced Device Physics(E), Solid State Physics and its Application to Electronics II(E), 応用物性数学特論, 先端デバイス特論(E), 固体電子物性・デバイス特論Ⅱ(E)

■Contributions to  Society

◆Academic Society Affiliations
International Conference on Hot-Wire Chemical Vapor Deposition (Cat-CVD) Process, 薄膜材料デバイス研究会, Active-Matrix Flatpanel Displays and Devices (AM-FPD), International Conference on Solid State Devices and Materials (SSDM), Cat-CVD研究会, IEEE, The Japan Society of Applied Physics

■Academic  Awards

・ PVSEC-27 Best Paper Award , PVSEC-27 Technical Program Committee , 2017
・ 第22回(2007年春季)応用物理学会講演奨励賞 , The Japan Society of Applied Physics , 2007