講演情報
[24p-P06-9]Investigation of Trap Defect States in Cu(In,Ga)Se2 Solar Cells via Temperature Dependent Transient Photocapacitance and Photocurrent Spectroscopy
〇(P)CheukKaiGary Kwok1, Naoki Masuko1, Shogo Ishizuka2, Roland Scheer3, Takeaki Sakurai1,2 (1.Faculty of Pure and Applied Science, Univ. of Tsukuba, 2.National Institute of Advanced Industrial Science and Technology (AIST), 3.Institute of Physics, Martin-Luther-Univ. Halle-Wittenberg)
キーワード：
Cu(In、Ga)Se2、transient photocapacitance、Configuration coordinate
Chalcopyrite Cu(In,Ga)Se2 (CIGSe) solar cells have demonstrated a high efficiency of 23.4% under one sun condition, among thin film photovoltaic (PV) technologies. However, CIGSe are inherently spatial inhomogeneous, and its properties can be affected by impurities and thermal disorder, and electrostatic potential fluctuations within a semiconductor as triggered by subgap charged defects. Realizing the origin and the mechanism of carrier trapping and recombination by probing the defect properties of CIGSe facilitates the advancement of PV technologies. In this work, we explore the properties of both subgap shallow defects and deep defects, in particular the trapping states, in the depletion region of the CIGSe/CdS solar cells, and the optical transitions for photoexcited electrons via multiple temperature dependent spectroscopic techniques, namely transient photocapacitance (TPC) and transient photocurrent (TPI) spectroscopies. The thermal and optical activation processes along the defect states are interpreted using a 1D configuration coordinate (CC) model, where electron-phonon interaction is considered.