Investigation of Se supply for the growth of CZTSSe thin films for photovoltaics

In this work, the selenization growth of Cu 2 ZnSn(SxSe 1−x ) 4 (CZTSSe) films was optimized by two groups of experiments in vacuum chamber. The selenization of CZTSSe is strongly dependent on the Se supply in the vacuum chamber. Insufficient Se supply left the selenization incomplete. Higher Se supply to CZTSSe either by increasing the Se powder usage or by increasing the external pressure resulted in the degradation of CZTSSe films with lower degree of crystallinity.The characterization of XRD, Raman and SEM confirmed the films obtained under the best conditions were well-developed CZTSSe films with compact faceted grains and good crystallinity. Additionally, theCZTSSe film grown using 500°C showed more orientation along (220).