Determination of deep-level defects in Cu2ZnSn(S,Se)4 thin-films using photocapacitance method

• Published in: Applied physics letters Vol. 106; no. 24
• Main Authors: Islam, Muhammad Monirul, Halim, Mohammad Abdul, Sakurai, Takeaki, Sakai, Noriyuki, Kato, Takuya, Sugimoto, Hiroki, Tampo, Hitoshi, Shibata, Hajime, Niki, Shigeru, Akimoto, Katsuhiro
• Format: Journal Article
• Language: English
• Published: Melville American Institute of Physics 15-06-2015
• Subjects: Applied physics; Comparative studies; Copper indium gallium selenides; Defects; Photocapacitance; Spectrum analysis; Thin films
• ISSN: 0003-6951; 1077-3118
• DOI: 10.1063/1.4922810

Deep-level defects were investigated in Cu2ZnSn(S,Se)4 and Cu2ZnSnS4 thin-films using transient photocapacitance (TPC) spectroscopy. A deep-defect, OH1 centered around 1.0 eV above the valance-band (EV) of Cu2ZnSnS4 has been identified at room temperature (RT). However, OH1-defect could be identified in Cu2ZnSn(S,Se)4 at low temperature only. Absence of OH1-defect in Cu2ZnSn(S,Se)4 at RT explains its better performance comparing to Cu2ZnSnS4 solar-cell. A comparative study of the TPC spectra of the Cu(In,Ga)Se2 solar-cells was performed. Low intensity of defect-signal together with lower broadening of exponential band-tail in the TPC spectra were attributed to superior performance of Cu(In,Ga)Se2 solar-cells comparing to Cu2ZnSn(S,Se) counterpart.