Temperature induced phase transformation in coevaporated Cu2SnSe3 thin films

Abstract

Cu2SnSe3 (CTSe) thin films were prepared by coevaporation at different substrate temperatures (325–400°C). The dependence of the phase transformation of CTSe thin films on the substrate temperature was investigated by X-ray diffraction and transmission electron microscopy analyses. The CTSe films grown at low temperatures (≤350°C) crystallized in the monoclinic phase and showed a strong preferential orientation of the (002) plane. The films grown at higher substrate temperatures (≥375°C) were randomly oriented with a cubic structure. A slight increase in the optical band gap from 0.84eV to 0.91eV was observed as substrate temperature was increased from 325°C to 400°C.