Influence of composition and annealing on the characteristics of Cu2SnS3 thin films grown by cosputtering at room temperature

This work aims to study the tolerance of Cu2SnS3 to both Cu-poor and Cu-rich stoichiometries. For this purpose, films were synthesized by RF magnetron sputtering of Cu2S and SnS2 targets. Films were crystallized and retained the tetragonal structure at room temperature, revealing the high stability of this material. A treatment at higher temperature leads to the formation of the metallic Cu3SnS4 phase. The results of optical and electrical measurements indicated that all the samples are p-type semiconductors with an energy band gap of 1.28 eV. A dependence of the electrical properties of the film with the Cu content and the annealing conditions was observed.