Photovoltaic properties in high-density self-organized type-II quantum dot superlattice

• Project/Area Number: 19H02541
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 28020:Nanostructural physics-related
• Research Institution: The University of Tokyo
• Principal Investigator: Okada Yoshitaka 東京大学, 先端科学技術研究センター, 教授 (40224034)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Project Status: Completed (Fiscal Year 2022)
• Budget Amount: ¥17,290,000 (Direct Cost: ¥13,300,000、Indirect Cost: ¥3,990,000); Fiscal Year 2022: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000); Fiscal Year 2021: ¥2,470,000 (Direct Cost: ¥1,900,000、Indirect Cost: ¥570,000); Fiscal Year 2020: ¥5,850,000 (Direct Cost: ¥4,500,000、Indirect Cost: ¥1,350,000); Fiscal Year 2019: ¥6,500,000 (Direct Cost: ¥5,000,000、Indirect Cost: ¥1,500,000)
• Keywords: 量子ドット太陽電池 / 量子ドット / 量子ナノ構造 / 自己組織化成長 / 分子線エピタキシー / 光閉じ込め技術 / 中間バンド太陽電池 / 分子線エピタキシ－ / タイプⅡヘテロ構造 / 自己組織化量子ドット / タイプⅡ超格子 / 光マネジメント / ナノ構造物理 / 光起電力物性 / 太陽電池 / 2段階光吸収 / 集光型太陽電池

Outline of Research at the Start

量子ドット・超格子等による最適な量子構造を光吸収層に導入した太陽電池の場合、現在の単結晶シリコン太陽電池の２倍の変換効率が可能である。中間バンドを用いた高効率化のアプローチにおいては、(1)中間バンド内の準位に光励起されたキャリアの寿命が十分長いこと、さらに(2)中間バンド→伝導帯への光励起が効率良く生じることが必須である。本研究では、これまでの高均一で高密度の量子ドット超格子の作製技術の成果を基に、量子ドット超格子中に形成される中間バンドを介した光電変換過程のメカニズム解明とその制御法を研究し、２段階光吸収過程による電流生成の最大化により高効率化を目指す。

Outline of Final Research Achievements

1) We have succeeded in a high quality growth of GaAsSb alloy in the form of quantum dots and quantum rings on GaAs(001) substrate by molecular beam epitaxy (MBE) with precise alloy composition. In GaAsSb/GaAs quantum ring solar cells, improved characteristics was observed due to the improvement of carrier lifetime.
2) We have succeeded in the fabrication of thin-film GaAsSb/GaAs quantum ring solar cells integrated with a Fabry-Perot light-trapping structure by using epitaxial lift-off (ELO) technique. We were able to demonstrate an improvement in both the short-circuit current and the open-circuit voltage of solar cell as a result of increased photon absorption as well as reduced recombination rates.

Academic Significance and Societal Importance of the Research Achievements

従来の InAs/GaAs 量子ドット太陽電池で課題となっていた開放電圧の低下が、低欠陥の量子リングの自己組織化成長とその多積層化技術の開発によって解決することができた。量子ナノ構造の物性評価において、量子ドットは弾性緩和が大きく室温では非発光再結合が大きな割合を占め、再現性の高い精密な物性評価やシミュレーション結果との照合が困難であった。一方の量子リングは弾性緩和が小さく非発光再結合が抑制され、また多積層化が実現できたことから、これまで測定が困難だった2段階吸収過程等の室温での評価を行いやすくなったと考えられる。

Research Products

• [Int'l Joint Research] CNRS/C2N(フランス)
• [Int'l Joint Research] ペンシルベニア州立大学(米国)
• [Int'l Joint Research] University of Cambridge(英国)
• [Int'l Joint Research] CNRS/C2N(フランス)
• [Int'l Joint Research] CNRS/C2N(フランス)
• [Int'l Joint Research] University of New South Wales(オーストラリア)
• [Int'l Joint Research] University of Cambridge(英国)
• [Int'l Joint Research] CNRS/Ecole Polytechnique(フランス)
• [Journal Article] Dependence of the radiative lifetime on the type-II band offset in GaAsxSb1－x/GaAs quantum dots including effects of photoexcited carriers (2022)
  • Author(s): Oteki Yusuke, Shoji Yasushi, Miyashita Naoya, Okada Yoshitaka
  • Journal Title: Journal of Applied Physics Volume: 132 Issue: 13 Pages: 134402-134402
  • DOI: 10.1063/5.0105306
  • Peer Reviewed
• [Journal Article] Enhanced current generation in quantum-dot intermediate band solar cells through optimizing the position of quantum dot layers (2022)
  • Author(s): Oteki Yusuke, Miyashita Naoya, Giteau Maxime, Shiba Kodai, Sogabe Tomah, Okada Yoshitaka
  • Journal Title: Optical Materials: X Volume: 16 Pages: 100207-100207
  • DOI: 10.1016/j.omx.2022.100207
  • Peer Reviewed / Open Access
• [Journal Article] Co-deposition of MoS2 films by reactive sputtering and formation of tree-like structures (2022)
  • Author(s): Kim Myeongok, Giteau Maxime, Ahsan Nazmul, Miyashita Naoya, Thirumalaisamy Logu, Chen Chen, Redwing Joan M, Okada Yoshitaka
  • Journal Title: Nanotechnology Volume: 33 Issue: 34 Pages: 345708-345708
  • DOI: 10.1088/1361-6528/ac70e3
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Properties of sputter-grown CuGaS2 absorber and CuGaS2/Cd1-xZnxS buffer heterointerface for solar cell application (2022)
  • Author(s): Myeongok Kim, Nazmul Ahsan, Zacharie Jehl, Yudania Sanchez, Yoshitaka Okada
  • Journal Title: Thin Solid Films Volume: 743 Pages: 139063-139063
  • DOI: 10.1016/j.tsf.2021.139063
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Study of sub-band states formation in the optical band gap of CuGaS2 thin films by electronic excitations (2022)
  • Author(s): S. Suba Viveka, T. Logu, N. Ahsan, K. Asokan, S. Kalainathan, K. Sethuraman, Y. Okada
  • Journal Title: Journal of Physics and Chemistry of Solids Volume: 164 Pages: 110636-110636
  • DOI: 10.1016/j.jpcs.2022.110636
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Optimizing the vertical position of quantum dots and wells to maximize light absorption (2021)
  • Author(s): Maxime Giteau, Yusuke Oteki, Kento Kitahara, Naoya Miyashita, Ryo Tamaki, Yoshitaka Okada
  • Journal Title: SPIE Proceedings, New Concepts in Solar and Thermal Radiation Conversion IV Volume: 11824 Pages: 1182406-1182406
  • DOI: 10.1117/12.2593862
  • Peer Reviewed
• [Journal Article] Experimental demonstration of energy-transfer ratchet intermediate-band solar cell (2021)
  • Author(s): Tomah Sogabe, Chao-Yu Hung, Ryo Tamaki, Stanko Tomic, Koichi Yamaguchi, Ned Ekins-Daukes, Yoshitaka Okada
  • Journal Title: Communications Physics Volume: 4 Issue: 1 Pages: 38-38
  • DOI: 10.1038/s42005-021-00543-1
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Temperature Dependence of Carrier Extraction Processes in GaSb/AlGaAs Quantum Nanostructure Intermediate-Band Solar Cells (2021)
  • Author(s): Shoji Yasushi、Tamaki Ryo、Okada Yoshitaka
  • Journal Title: Nanomaterials Volume: 11 Issue: 2 Pages: 344-344
  • DOI: 10.3390/nano11020344
  • Peer Reviewed / Open Access
• [Journal Article] Identification of surface and volume hot-carrier thermalization mechanisms in ultrathin GaAs layers (2020)
  • Author(s): M. Giteau, E. de Moustier, D. Suchet, H. Esmaielpour, H. Sodabanlu, K. Watanabe, S. Collin, J-F Guillemoles, Y. Okada
  • Journal Title: Journal of Applied Physics Volume: 128 Issue: 19 Pages: 193102-193102
  • DOI: 10.1063/5.0027687
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Engineering of sub-band in CuGaS2 thin films via Mo doping by chemical spray pyrolysis route (2020)
  • Author(s): Logu Thirumalaisamy, Nazmul Ahsan, Kalainathan Sivaperuman, Myeongok Kim, Sethuraman Kunjithapatham, Yoshitaka Okada
  • Journal Title: Thin Solid Films Volume: 709 Pages: 138252-138252
  • DOI: 10.1016/j.tsf.2020.138252
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Photoabsorption improvement in multi-stacked InGaAs/GaAs quantum dot (2020)
  • Author(s): Y. Shoji, K. Watanabe, and Y. Okada
  • Journal Title: Solar Energy Materials & Solar Cells Volume: 204 Pages: 110216-110216
  • DOI: 10.1016/j.solmat.2019.110216
  • Peer Reviewed / Open Access
• [Journal Article] Detailed balance calculations for hot-carrier solar cells: coupling high absorptivity with low thermalization through light trapping (2019)
  • Author(s): M. Giteau, D. Suchet, S. Collin, J.-F. Guillemoles and Y. Okada
  • Journal Title: EPJ Photovoltaics Volume: 10 Pages: 1-1
  • DOI: 10.1051/epjpv/2019001
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] Nanoscale Wet Chemical Engineering of III-V Quantum Dots for Emerging Solar Applications (2019)
  • Author(s): M. Bouttemy, D. Aureau, M. Fregnaux, Y. Shoji, Z. Jehl, D. Suchet, J.-F. Guillemoles, A. Etcheberry, and Y. Okada
  • Journal Title: ECS Meeting Abstracts Volume: 89 Issue: 24 Pages: 37-46
  • DOI: 10.1149/ma2019-01/24/1230
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] A hot-carrier assisted InAs/AlGaAs quantum-dot intermediate-band solar cell (2019)
  • Author(s): B. Behaghel, R. Tamaki, H.-L. Chen, P. Rale, L. Lombez, Y. Shoji, A. Delamarre, A. Cattoni, S. Collin, Y. Okada, and J.-F. Guillemoles
  • Journal Title: Semiconductor Science and Technology Volume: 34 Issue: 8 Pages: 084001-084001
  • DOI: 10.1088/1361-6641/ab23d0
  • Peer Reviewed / Int'l Joint Research
• [Journal Article] Current transport efficiency analysis of multijunction solar cells by luminescence imaging (2019)
  • Author(s): H. Xu, A. Delamarre, B. M. F. Yu Jeco, H. Johnson, K. Watanabe, Y. Okada, J.-F. Guillemoles, Y. Nakano, and M. Sugiyama
  • Journal Title: Progress in Photovoltaics: Research and Applications Volume: 27 Issue: 10 Pages: 835-843
  • DOI: 10.1002/pip.3140
  • Peer Reviewed / Int'l Joint Research
• [Presentation] Optimizing the positions of quantum dot layers for light absorption enhancement in quantum dot solar cells with light trapping (2022)
  • Author(s): Y. Oteki, N. Miyashita, M. Giteau, K. Kitahara, Y. Okada
  • Organizer: 8th World Conference on Photovoltaic Energy Conversion
  • Int'l Joint Research
• [Presentation] Demonstration of Energy-Transfer Ratchet Intermediate-Band Solar Cells Using Erbium-Doped GaAs (2022)
  • Author(s): Yoshitaka Okada, Tomah Sogabe, Chao-Yu Hung, Ryo Tamaki
  • Organizer: 22nd International Vacuum Congress
  • Int'l Joint Research
• [Presentation] Effect of Off-angle on the Epitaxial Growth of MoS2 on Off-angle Sapphire by Metal-organic Chemical Vapor Deposition (2022)
  • Author(s): Myeongok Kim, Nazmul Ahsan, Chen Chen, Dorota A. Kowalczyk, Nicholas Trainor, Joan M. Redwing, Yoshitaka Okada
  • Organizer: 9th International Symposium on Control of Semiconductor Interfaces
  • Int'l Joint Research
• [Presentation] 薄型量子ドット太陽電池における光閉じ込め構造と光吸収の増大 (2022)
  • Author(s): 北原健渡, 樗木悠亮, 宮下直也, 岡田至崇
  • Organizer: 第19 回「次世代の太陽光発電システム」シンポジウム（第 2 回日本太陽光発電学会学術講演会）
• [Presentation] Fabry-Perot光閉じ込め構造を用いた薄膜量子ドット太陽電池の評価 (2022)
  • Author(s): 樗木悠亮, 北原健渡, 宮下直也, 岡田至崇
  • Organizer: 第93回 応用物理学会秋季学術講演会
• [Presentation] 光閉じ込め構造を用いたGaSb/GaAs量子リング中間バンド型太陽電池 (2022)
  • Author(s): 樗木悠亮, 岡田至崇
  • Organizer: 2022年度多元系化合物・太陽電池研究会年末講演会
• [Presentation] Enabling hot-carrier solar cells by combining ultrathin quantum absorbers with light trapping (2022)
  • Author(s): Maxime Giteau, Yoshitaka Okada他
  • Organizer: SPIE Photonics West 2022
  • Int'l Joint Research / Invited
• [Presentation] 薄膜中間バンド型太陽電池の電流増大に向けた量子ドット位置の最適化 (2022)
  • Author(s): 樗木悠亮、北原健渡、宮下直也、岡田至崇
  • Organizer: 第69回応用物理学会春季学術講演会
• [Presentation] Epitaxial Growth of MoS2 on Sapphire (c-Al2O3) by MOCVD (2022)
  • Author(s): Myeongok Kim, Nazmul Ahsan, Nicholas Trainor, Chen Chen, Dorota Kowalczyk, Joan Redwing, Yoshitaka Okada
  • Organizer: 第69回応用物理学会春季学術講演会
• [Presentation] Approaches to high-efficiency intermediate band photovoltaics (2021)
  • Author(s): Yoshitaka Okada
  • Organizer: European MRS Spring 2021
  • Int'l Joint Research / Invited
• [Presentation] Fabry-Perot共振を用いた量子ドット太陽電池の光吸収率増強 (2021)
  • Author(s): 樗木悠亮、Maxime Giteau、福島啓、北原健渡、宮下直也、玉置亮、岡田至崇
  • Organizer: 第68回応用物理学会春季学術講演会
• [Presentation] 光閉じ込め効果を用いたInAs/GaAs量子ドット太陽電池の光吸収特性解析 (2020)
  • Author(s): 福島 啓、Maxime Giteau、岡田至崇
  • Organizer: 第81回応用物理学会秋季学術講演会
• [Presentation] エピタキシャルリフトオフ法を用いた薄膜太陽電池の作製 (2020)
  • Author(s): 宮下直也、岡田至崇
  • Organizer: 第81回応用物理学会秋季学術講演会
• [Presentation] Optimizing the structure of quantum dot intermediate-band solar cells (2019)
  • Author(s): Yoshitaka Okada
  • Organizer: 30th World Nano Conference (NANO30)
  • Int'l Joint Research / Invited
• [Presentation] Epitaxial Lift-Off of Ultrathin Heterostructures for Hot-Carrier Solar Cell Applications (2019)
  • Author(s): M. Giteau, K. Watanabe, H. . Sugiyama, A. Cattoni, S. Collin, J.-F. Guillemoles, and Y. OkadaSodabanlu, N. Miyashita, M
  • Organizer: Compound Semiconductor Week 2019 (CSW2019)
  • Int'l Joint Research
• [Presentation] Quantum Dot Photovoltaics: Challenges Towards 50% Efficiency (2019)
  • Author(s): Yoshitaka Okada
  • Organizer: 10th International Conference on Materials for Advanced Technologies (ICMAT2019)
  • Int'l Joint Research / Invited
• [Presentation] High-Efficiency InAs-InGaAs Quantum Dash Solar Cells Developed Through Current Constraint Engineering (2019)
  • Author(s): Y. Okada, N. Miyashita, Y. Oteki, and Y. Shoji
  • Organizer: 46th IEEE Photovoltaic Specialists Conference (PVSC46)
  • Int'l Joint Research
• [Presentation] Progress and Approaches to High-Efficiency Intermediate Band Photovoltaics (2019)
  • Author(s): Yoshitaka Okada
  • Organizer: 7th International Workshop on Epitaxial Growth and Fundamental Properties of Semiconductor Nanostructures (SemiconNano 2019)
  • Int'l Joint Research / Invited
• [Book] PHOTOVOLTAICS FOR SPACE: KEY ISSUES, MISSIONS, AND ALTERNATIVE TECHNOLOGIES (Ch.10 Inverted lattice-matched GaInP/GaAs/GaInNAsSb triple-junction solar cells: Epitaxial lift-off thin-film devices and potential space applications) (2022)
  • Author(s): Naoya Miyashita, Yoshitaka Okada
  • Total Pages: 505
  • Publisher: Elsevier
  • ISBN: 9780128233009
• [Book] Semiconductor Nanodevices, Frontiers of Nanoscience (Ch.10 Semiconductor quantum dot solar cells) (2022)
  • Author(s): Yoshitaka Okada, Katsuhisa Yoshida, Yasushi Shoji, Ryo Tamaki
  • Total Pages: 498
  • Publisher: Elsevier
  • ISBN: 9780128220832
• [Remarks] 東京大学先端科学技術研究センター岡田研究室
  • URL: https://mbe.rcast.u-tokyo.ac.jp/