Temperature induced phase transformation in coevaporated Cu_2SnSe_3 thin films

摘要

Cu_2SnSe_3 (CTSe) thin films were prepared by coevaporation at different substrate temperatures (325-400 ℃). 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 ℃) crystallized in the monoclinic phase and showed a strong preferential orientation of the (002) plane. The films grown at higher substrate temperatures (≥ 375 ℃) were randomly oriented with a cubic structure. A slight increase in the optical band gap from 0.84 eV to 0.91 eV was observed as substrate temperature was increased from 325 ℃ to 400 ℃.