Updated on 2022/08/25

写真a

 
Keigou Maejima
 
Organization
Research Field in Engineering, Science and Engineering Area Graduate School of Science and Engineering (Engineering) Department of Engineering Electrical and Electronics Engineering Program Associate Professor
Title
Associate Professor

Degree

  • 博士（工学） ( 2006.7   京都大学 )

Research Areas

  • Others / Others  / 薄膜

  • Others / Others  / 酸化物

  • Others / Others  / 半導体

Research History

  • Kagoshima University   Research Field in Engineering, Science and Engineering Area Graduate School of Science and Engineering (Engineering) Department of Engineering Electrical and Electronics Engineering Program   Associate Professor

    2020.4

  • Kagoshima University   Research Field in Engineering, Science and Engineering Area Graduate School of Science and Engineering (Engineering) Electrical and Electronics Engineering Course   Associate Professor

    2015.4 - 2020.3

Professional Memberships

  • 日本化学会

    2007.1

  • 応用物理学会

    2001.6

 

Papers

  • Hitoshi Sai, Keigou Maejima, Takuya Matsui, Takashi Koida, Koji Matsubara, Michio Kondo, Yoshiaki Takeuchi, Hirotaka Katayam, Isao Yoshida .  Effect of Front TCO Layer on Properties of Substrate-Type Thin-Film Microcrystalline Silicon Solar Cells .  IEEE Journal of Photovoltaics5 ( 6 ) 1528 - 1533   2015.10Effect of Front TCO Layer on Properties of Substrate-Type Thin-Film Microcrystalline Silicon Solar CellsReviewed

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher： IEEE  

    Power conversion efficiency of thin-film microcrystalline silicon solar cells has been remarkably improved recently: from 10.1% to 11.8%. Front transparent conductive oxide (TCO) films have played an important role in this efficiency improvement. In this study, the impact of the front TCO films was investigated by comparing microcrystalline silicon solar cells with In2O3:Sn films grown by sputtering and ZnO:B films grown by metal-organic chemical vapor deposition (MOCVD). Improvement mechanisms in open-circuit voltages and fill factors in solar cells are investigated and discussed.

    DOI： 10.1109/JPHOTOV.2015.2478030

  • Takuya Matsui, Keigou Maejima, Adrien Bidiville, Hitoshi Sai, Takashi Koida, Takashi Suezaki, Mitsuhiro Matsumoto, Kimihiko Saito, Isao Yoshida, Michio Kondo .  High-efficiency thin-film silicon solar cells realized by integrating stable a-Si:H absorbers into improved device design .  Japanese Journal of Applied Physics54 ( 8S1 ) 08KB10   2015.7High-efficiency thin-film silicon solar cells realized by integrating stable a-Si:H absorbers into improved device designReviewed

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Applied Physics  

    We report that thin-film silicon solar cells exhibiting high stabilized efficiencies can be obtained by depositing hydrogenated amorphous silicon (a-Si:H) absorbers using triode-type plasma-enhanced chemical vapor deposition. The improved light-soaking stability and performance of solar cells are also realized by optimizing the device design, such as p and p–i buffer layers. As a result, we attain independently confirmed stabilized efficiencies of 10.1–10.2% for a-Si:H single-junction solar cells (absorber thickness: ti = 220–310 nm) and 12.69% for an a-Si:H (ti = 350 nm)/hydrogenated microcrystalline silicon (µc-Si:H) tandem solar cell fabricated using textured SnO2 and ZnO substrates, respectively. The relative efficiency degradations of these solar cells are ~10 and 3%, respectively, under 1 sun illumination at 50 °C for 1000 h.

  • Hitoshi Sai, Keigou Maejima, Takuya Matsui, Takashi Koida, Michio Kond, Sachiko Nakao, Yoshiaki Takeuchi, Hirotaka Katayam, Isao Yoshida .  High-efficiency microcrystalline silicon solar cells on honeycomb textured substrates grown with high-rate VHF plasma-enhanced chemical vapor deposition .  Japanese Journal of Applied Physics54 ( 8S1 ) 08KB05   2015.7High-efficiency microcrystalline silicon solar cells on honeycomb textured substrates grown with high-rate VHF plasma-enhanced chemical vapor depositionReviewed

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    Language：English   Publishing type：Research paper (scientific journal)   Publisher：The Japan Society of Applied Physics  

    The potential of high-rate growth of high-quality microcrystalline silicon (µc-Si:H) films for solar cell applications is investigated by very high frequency plasma-enhanced chemical vapor deposition (VHF-PECVD) under a high-pressure SiH4 depletion condition. It is found that the morphology of textured substrates plays an important role in not only light trapping but also µc-Si:H film growth. A high conversion efficiency of 11.1% is attained in a substrate-type µc-Si:H cell on a substrate with honeycomb textures, which has rounded concaves in a honeycomb arrangement with an appropriate period. It is also clarified that ZnO:B films grown by metal organic chemical vapor deposition (MOCVD) are beneficial in terms of carrier collection compared with the standard In2O3:Sn (ITO) film grown by sputtering. On the basis of these findings, a new world-record µc-Si:H cell with a certified conversion efficiency of 11.8% is developed with a relatively high deposition rate of 1 nm/s.

  • Keigou Maejima, Takashi Koida, Hitoshi Sai, Takuya Matsui, Kimihiko Saito, Michio Kondo, and Teiji Takagawa .  Influences of deposition temperature on characteristics of B-doped ZnO films deposited by metal-organic chemical vapor deposition .  Thin Solid Films559   83 - 87   2014.5Influences of deposition temperature on characteristics of B-doped ZnO films deposited by metal-organic chemical vapor depositionReviewed

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    Authorship：Lead author   Language：English   Publishing type：Research paper (international conference proceedings)  

  • 前島圭剛 .  有機金属気相成長法ZnOの成長形に関する研究 .      2006.7有機金属気相成長法ZnOの成長形に関する研究

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    Language：Japanese   Publishing type：Doctoral thesis  

Presentations