Cu 2ZnSnSe 4 films by selenization of Sn–Zn–Cu sequential films

Abstract

This paper deals with the formation of Cu 2ZnSnSe 4 (CZTS) in the process of selenization of metal precursor layers in elemental selenium vapour. Metallic precursors were sequentially evaported from Sn, Zn and Cu sources. Precursor Sn–Zn–Cu films have a “mesa-like” structure and consist mainly of Cu 5Zn 8 and Cu 6Sn 5 phases. It was confirmed that the formation of different binary copper selenides is the dominating process of selenization in elemental Se vapour at temperatures up to 300 °C. The formation of kesterite CZTS films begins at 300 °C and dominates at higher temperatures, always resulting in multiphase films that consist of high-quality Cu 2ZnSnSe 4 crystals and of a separate phase of ZnSe.