Investigating optical, structural and morphological properties of Cu_xZn_1-xS thin films

Abstract Cu x Zn 1-x S (CZS) Nano crystallized thin films with (x=0.25,0.5,0.75) were grown from alloy by thermal evaporation technique on glasses substrates at room temperature in a vacuum ∼ 2 × 10 −5 mbar with 450±20 nm thickness. The Cu content concentration effects on structure, morphology besides optically property of these films were investigated. X-ray diffraction (XRD) technique and Atomic force microscopy (AFM) were used to investigation the structural and morphological properties of Cu x Zn 1-x S films. XRD analysis offered that these films had poly crystalline hexagonal structure with preferred orientation along (201) plane and mixed of of CuS-ZnS structure. The crystallites size changing with Cu concentration were found as (4.12, 5.5, 8.4) nm respectively. Using AFM measurements to investigate morphological properties of these films, the grain size for Cu x Zn 1-x S films differs with Cu content thru uniform distribution. UV-Vis absorption spectroscopy was used to investigation the optical characterization of Cu x Zn 1-x S films as a function of Cu content. The direct band gap values of these films were found decrease with increasing Cu content as (2.45, 2.4, and 2.3) eV respectively and the optical constant affected with Cu content. The Cu x Zn 1-x S films have suitable optical characteristics which can used it for solar cell applications.