Influence of substrate temperature on CuxSnSx+1 thin films prepared by Co-sputtering and H2S annealing

Abstract

CuxSnSx+1 (CTS) thin films were deposited by co-sputtering of Cu and Sn targets and annealing the films in an Ar:H2S atmosphere. The substrate temperatures were fixed at room temperature, 100, 175, and 250 °C during film deposition. The deposited films were then annealed in an Ar:H2S atmosphere at 550 °C for 1 h. The Cu/Sn ratio decreased sharply with substrate temperature. In the annealed samples, the Cu/Sn ratio increased for films deposited at room temperature, 100, and 175 °C, and decreased for films deposited at 250 °C, showing the temperature dependence of CuxSn alloy formation. Additionally, Cu3SnS4 phase formation was observed in the films grown at room temperature, whereas the films showed a Cu2SnS3 phase at higher substrate temperatures.