The Influence of Layer Number on Properties of Cu2ZnSnS4 Films

Abstract

In present study, Cu2ZnSnS4 thin films were deposited via single-step sol-gel spin coating process. The effect of layer number on the structural, morphological and optical properties was investigated. XRD results showed that 7 layered film had crystal structure but other films had amorphous structure. 7 layered film grown at (112) preferential orientation and it had another peak of (200). AFM analysis indicated that any particle on surface of 3, 4 and 5 layered films was not observed and the particle structure was observed for 6 and 7 layer films. The crystallite sizes for 6 layer films were very small, but 7 layer films had both small and big particles on its surface. This particle structure was not homogenous for the film surfaces. From UV-VIS studies, optical band gap of 3, 4, 5, 6 and 7 layered films were found to be 1.88 eV, 1.82 eV, 1.73 eV, 1.68 eV and 1.48 eV, respectively. This result indicates that 7 layered film is very suitable for solar cell as an absorber layer.