LAUSR

Abstract Cu2SnS3 (CTS) thin films have been investigated extensively as an absorber layer for photovoltaic applications owing to the use of low-cost and earth-abundant materials. However, the performance of CTS solar cells still suffers from voltage deficit, resulting in a low value of open-circuit voltage (Voc). In this study, we introduce a Ge layer into CTS materials using Ge metal target as a doping source. Subsequently, the sputtered Cu/Ge/Sn precursors are sulfurized under sulfur vapor ambient to form a Cu2(Sn,Ge)S3 (CTGS) thin film. Meanwhile, we also fabricate a CTS solar cell under the same experimental conditions as compared with CTGS solar cell. The Ge layer of thickness approximately 20 nm enhanced the efficiency from 0.45% (CTS) to 3.05% (CTGS), whereas the improvement in performance was limited for Ge layer of thickness more than 20 nm.