The influence of post treatment on physical properties of polycrystalline CuInS2 thin films

Abstract

In this paper, CuInS2 (CIS) films were prepared by vacuum evaporation method and the soda-lime glass was used as substrate. Crushed CIS powder from polycrystalline CIS ingot was used as starting materials. Then, as prepared CIS films were heat treated in S atmosphere at 400°C for 30min. After annealed, some CIS films were etched by argon plasma or bromine methanol (BM) mixed solution. The results of XRD patterns showed that the argon plasma treatment could remove the CuxS phases on the surface of CIS films perfectly. After argon plasma treatment, the conduction type of the CIS films showed no change, which indicated that argon plasma treatment had no specific selectivity for the elimination of surface atoms. Moreover, as the results of EDX measurement of CIS films, the Cu/In atomic ratio showed a monotonic decreasing tendency with the increasing time of BM solution etching, which might be related to the preferential corrosion of BM solution. Furthermore, the results of Hall measurement also showed that after the etching of BM solution, the conduction type of CIS films was changed from p type to n type due to the preferential corrosion of BM solution, which was consistent with the results of previous published paper.