Surface statistical properties of solid state reacted CZTSe compounds prepared in five different ratios

Abstract

Copper Zinc Tin Selenide (CZTSe) has attracted much attention in recent times, for an absorber layer in thin film solar cells, due to high natural abundance of its constituents and their non-toxicity. In this work preparation of CZTSe compounds through solid state reaction of elemental precursors, namely Cu, Zn, Sn and Se and study of surface roughness, using the atomic force microscopy (AFM) has been presented. In order to study the influence of compositional variation on surface morphology, quantitative roughness and surface characteristics have been evaluated from AFM characterization. Surface roughness and grain size along with parameters like surface kurtosis, skewness and root mean square (RMS) roughness have been discussed. A significant difference has been observed in roughness parameters and grain size with respect to Cu/Zn variations. It has been concluded that deficiency of Cu and excess of Zn, caused decrement in mean grain size of the material with respect to perfect stoichiometric sample. These observations have also been verified using SEM-EDAX and FTIR studies.