Effect of thermal pretreatment of metal precursor on the properties of Cu2ZnSnS4 films**Project supported by Funding for Outstanding Doctoral Dissertation in NUAA, China (Grant No. BCXJ13-12), the Jiangsu Innovation Program for Graduate Education, China (Grant No. CXLX13_150), the Fundamental Research Funds for the Central Universities, China (Grant No. 61176062), the Science and Technology Supporting Project of Jiangsu Province, China (Grant

Abstract

Zn/Sn/Cu (CZT) stacks were prepared by RF magnetron sputtering. The stacks were pretreated at different temperatures (200 °C, 300 °C, 350 °C, and 400 °C) for 0.5 h and then followed by sulfurization at 500 °C for 2 h. Then, the structures, morphologies, and optical properties of the as-obtained Cu2ZnSnS4 (CZTS) films were studied by x-ray diffraction (XRD), Raman spectroscopy, UV–Vis–NIR, scanning electron microscope (SEM), and energy-dispersive x-ray spectroscopy (EDX). The XRD and Raman spectroscopy results indicated that the sample pretreated at 350 °C had no secondary phase and good crystallization. At the same time, SEM confirmed that it had large and dense grains. According to the UV–Vis–NIR spectrum, the sample had an absorption coefficient larger than 104 cm−1 in the visible light range and a band gap close to 1.5 eV.