Compositional disparity in Cu2ZnSnS4 (CZTS) thin film deposited by RF-sputtering from a single quaternary compound target

Abstract

Cu2ZnSnS4 (CZTS) is highly researched photovoltaic (PV) material in recent years because of resource availability and non-toxicity of its constituents. Radio frequency (RF) magnetron sputtering is one of the potential methods of fabricating CZTS thin film due to its suitability for large scale industrial implementation. Of the three methods of depositing CZTS films by RF sputtering, one step single quaternary target sputtering is by far the simplest and straightforward one. However, deposition profile plays a crucial role in maintaining the integrity of pre-defined target composition transferred to glass substrates. In this study, several deposition parameters, such as RF power, working pressure, and target to sample distance were varied and their influences on corresponding compositional variation in deposited samples were studied. A quaternary CZTS target with pre-fixed composition (Cu = 22%, Zn = 15%, Sn = 13%, S = 50%) was used to deposit CZTS thin films at various depositing conditions. Among all deposition profiles, high RF power was found to be more detrimental with high Cu loss up to 53% from the original atomic composition. © 2018 Elsevier B.V.