中国物理B ›› 2022, Vol. 31 ›› Issue (11): 116103-116103.doi: 10.1088/1674-1056/ac685f

所属专题： SPECIAL TOPIC — Emerging photovoltaic materials and devices

• • 上一篇    下一篇

Defect physics of the quasi-two-dimensional photovoltaic semiconductor GeSe

Saichao Yan(闫赛超)1,2, Jinchen Wei(魏金宸)1, Shanshan Wang(王珊珊)1, Menglin Huang(黄梦麟)2, Yu-Ning Wu(吴宇宁)1,†, and Shiyou Chen(陈时友)1,2,‡   

  1. 1 Key Laboratory of Polar Materials and Devices(MOE) and Department of Electronics, East China Normal University, Shanghai 200241, China;
    2 State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
  • 收稿日期:2022-01-13 修回日期:2022-04-14 接受日期:2022-04-20 出版日期:2022-10-17 发布日期:2022-10-19
  • 通讯作者: Yu-Ning Wu, Shiyou Chen E-mail:ynwu@phy.ecnu.edu.cn;chensy@fudan.edu.cn
  • 基金资助:
    This work was supported by Shanghai Academic/Technology Research Leader (Grant No. 19XD1421300), the National Natural Science Foundation of China (Grant No. 12174060), Program for Professor of Special Appointment (Eastern Scholar TP2019019), the National Key Research and Development Program of China (Grant No. 2019YFE0118100), State Key Laboratory of ASIC & System (Grant No. 2021MS006) and Young Scientist Project of MOE Innovation Platform.

Defect physics of the quasi-two-dimensional photovoltaic semiconductor GeSe

Saichao Yan(闫赛超)1,2, Jinchen Wei(魏金宸)1, Shanshan Wang(王珊珊)1, Menglin Huang(黄梦麟)2, Yu-Ning Wu(吴宇宁)1,†, and Shiyou Chen(陈时友)1,2,‡   

  1. 1 Key Laboratory of Polar Materials and Devices(MOE) and Department of Electronics, East China Normal University, Shanghai 200241, China;
    2 State Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
  • Received:2022-01-13 Revised:2022-04-14 Accepted:2022-04-20 Online:2022-10-17 Published:2022-10-19
  • Contact: Yu-Ning Wu, Shiyou Chen E-mail:ynwu@phy.ecnu.edu.cn;chensy@fudan.edu.cn
  • Supported by:
    This work was supported by Shanghai Academic/Technology Research Leader (Grant No. 19XD1421300), the National Natural Science Foundation of China (Grant No. 12174060), Program for Professor of Special Appointment (Eastern Scholar TP2019019), the National Key Research and Development Program of China (Grant No. 2019YFE0118100), State Key Laboratory of ASIC & System (Grant No. 2021MS006) and Young Scientist Project of MOE Innovation Platform.

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摘要： GeSe has recently emerged as a photovoltaic absorber material due to its attractive optical and electrical properties as well as earth abundancy and low toxicity. However, the efficiency of GeSe thin-film solar cells (TFSCs) is still low compared to the Shockley-Queisser limit. Point defects are believed to play important roles in the electrical and optical properties of GeSe thin films. Here, we perform first-principles calculations to study the defect characteristics of GeSe. Our results demonstrate that no matter under the Ge-rich or Se-rich condition, the Fermi level is always located near the valence band edge, leading to the p-type conductivity of undoped samples. Under Se-rich condition, the Ge vacancy (VGe) has the lowest formation energy, with a (0/2-) charge-state transition level at 0.22 eV above the valence band edge. The high density (above 1017 cm-3) and shallow level of VGe imply that it is the p-type origin of GeSe. Under Se-rich growth condition, Sei has a low formation energy in the neutral state, but it does not introduce any defect level in the band gap, suggesting that it neither contributes to electrical conductivity nor induces non-radiative recombination. In addition, Gei introduces a deep charge-state transition level, making it a possible recombination center. Therefore, we propose that the Se-rich condition should be adopted to fabricate high-efficiency GeSe solar cells.

关键词: GeSe bulk, point defect, concentration, photovoltaic

Abstract: GeSe has recently emerged as a photovoltaic absorber material due to its attractive optical and electrical properties as well as earth abundancy and low toxicity. However, the efficiency of GeSe thin-film solar cells (TFSCs) is still low compared to the Shockley-Queisser limit. Point defects are believed to play important roles in the electrical and optical properties of GeSe thin films. Here, we perform first-principles calculations to study the defect characteristics of GeSe. Our results demonstrate that no matter under the Ge-rich or Se-rich condition, the Fermi level is always located near the valence band edge, leading to the p-type conductivity of undoped samples. Under Se-rich condition, the Ge vacancy (VGe) has the lowest formation energy, with a (0/2-) charge-state transition level at 0.22 eV above the valence band edge. The high density (above 1017 cm-3) and shallow level of VGe imply that it is the p-type origin of GeSe. Under Se-rich growth condition, Sei has a low formation energy in the neutral state, but it does not introduce any defect level in the band gap, suggesting that it neither contributes to electrical conductivity nor induces non-radiative recombination. In addition, Gei introduces a deep charge-state transition level, making it a possible recombination center. Therefore, we propose that the Se-rich condition should be adopted to fabricate high-efficiency GeSe solar cells.

Key words: GeSe bulk, point defect, concentration, photovoltaic

中图分类号:  (Point defects and defect clusters)

  • 61.72.J-
61.50.Ah (Theory of crystal structure, crystal symmetry; calculations and modeling) 71.20.Nr (Semiconductor compounds)