Vapor transport deposited Sb2(S,Se)3 thin film: Effect of deposition temperature and Sb2S3/Sb2Se3 mass ratio

Abstract

The vapor transport deposition (VTD) processing is an effective and low-cost techniques to fabricate antimony selenosulfide (Sb2(S,Se)3) photovoltaic materials with large grains and preferred crystal orientations. Currently, the influences of various single deposition conditions of VTD on performances of Sb2(S,Se)3 solar cells have been studied, but which parameter should be optimized and how it affects is a noteworthy issue. Herein, the effects of two important deposition parameters, deposition temperature and mass ratio of Sb2S3/Sb2Se3 on the structure and photo-electrochemical properties of Sb2(S,Se)3 were investigated, and the mechanism of their impact on the growth of thin film was also discussed. It found that the (hk1) orientation growth of Sb2(S,Se)3 was dominated by Sb-Se bonds at deposition temperatures ranging from 460 °C to 500 °C. As the temperature increased, the S content in the film decreased. When the deposition temperature was fixed at 480 °C, it was found that the effect of the mass ratio of Sb2S3/Sb2Se3 on the growth was more about adjusting the concentration of Se than increasing the bonding of Sb-S. The introduced S can make the film smooth and dense, and also induce the growth of film in the (hk1) orientation when mass ratio is coupled with deposition temperature. Furthermore, the results of photo-electrochemical measurement indicated that photocurrent density is related to S content and preferred orientation. By adjusting the mass ratio, flat Sb2(S,Se)3 films were obtained with band gaps ranging from 1.24 eV to 1.42 eV and carrier concentrations ranging from 9.62 × 1014 cm−3 to 1.62 × 1015 cm−3, exhibiting good absorption layer characteristics.