Eliminating the excess CuxSe phase in Cu-rich Cu(In,Ga)Se2 by In2Se3 treatment

• Published in: Journal of alloys and compounds Vol. 709; pp. 31 - 35
• Main Authors: Peng, Xiao, Zhao, Ming, Zhuang, Daming, Guo, Li, Ouyang, Liangqi, Sun, Rujun, Zhang, Leng, Wei, Yaowei, Zhan, Shilu, Lv, Xunyan, Wu, Yixuan, Ren, Guoan
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 30-06-2017; Elsevier BV
• Subjects: Annealing; Atomic force microscopy; C-AFM; Copper; Copper indium gallium selenides; Cu-rich chalcopyrite; CuxSe distribution; In2Se3 treatment; Leakage; Methanol bromine etching; Photovoltaic cells; Solar cell; Solar cells; Solar energy; Thin films; Solar cell; Methanol bromine etching; CuxSe distribution; Cu-rich chalcopyrite; C-AFM; In2Se3 treatment
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2017.03.142

The residual CuxSe phase results in shunt leakage paths in Cu-rich Cu(In,Ga)Se2 (CIGS) which can cause serious degradation in the conversion efficiency. The conductive atom force microscopy(C-AFM) was employed to obtain a direct evidence of shunt leakage paths in the Cu-rich CIGS thin film. The results reveal that CuxSe phase exists not only near the surface but also inside the Cu-rich CIGS thin films. In order to eliminate the residual CuxSe, it is recommended to deposit a thin layer of In2Se3 on Cu-rich CIGS with subsequent annealing treatment (In2Se3 treatment for short). The In2Se3 treatment can effectively remove CuxSe phase as well as the shunt leakage paths in Cu-rich CIGS thin films and improve the efficiency of Cu-rich CIGS based solar cells from 1.2% to 9.5%.
•The excess CuxSe phase exists not only near the surface but also inside the Cu-rich CIGS thin films.•Direct evidence of shunt leakage paths in the Cu-rich CIGS thin film is obtained.•The excess CuxSe phase can be effectively removed by In2Se3 treatment.