A Comparative study of kesterite thin films prepared from different ball milled precursors

Abstract

Understanding the role of chalcogens (S & Se) is critical and challenging due to complex nature of kesterite compounds. Kesterite structure based CZTS/Se (Cu2ZnSnS/Se4) thin films were prepared from Cu-Zn-Sn-S, Cu-Zn-Sn-Se and Cu-Zn-Sn-S-Se precursors by subsequent selenization. This study compared the CZTSSe (Cu2ZnSn(S,Se)4) films prepared by the selenization of S and (S+Se) containing precursors. Pure Se based CZTSe (Cu2ZnSnSe4) film was also prepared from Cu-Zn-Sn-Se precursor. The properties of precursor powders were studied by means of XRD, TG-DSC and TEM. Phase formation of the three ball milled precursor (S, Se & S+Se) and thermal behavior was found to be significantly different. Compactness and grain growth were found better in case of film formed by selenization of Se & (S+Se) containing precursors. The impact of different chalcogen sources of precursors reflected in the structure, morphology, composition and band gap values of films. The present study offers new insight into the role of different chalcogen sources in the precursor, on the films prepared. Interesting aspects of structure, morphology and composition were explored for the precursors and the films. Various micro structural parameters such as strain & dislocation density along with penetration depth were calculated from XRD plots & are discussed. © 2017 Elsevier Ltd.