Preparation of CuInS2 thin films by electrodeposition and sulphurisation for applications in solar cells

Abstract

Thin films of copper indium disulphide (CuInS2) were grown on Ti substrates by sulpherisation of Cu–In precursors prepared by sequentially electrodeposited Cu and In layers. CuInS2 films were characterised using X-ray diffraction (XRD), scanning electron micrographs (SEM), diffuse optical reflectance, spectral response and capacitance–voltage (C–V) measurements. It was observed that the Cu/In atomic ratio of initial Cu–In precurser determines the composition of the CuInS2 films. XRD measurements revealed that single-phase polycrystalline CuInS2 thin films can be obtained by optimising the thickness of the Cu and In layers. SEM showed that polycrystalline CuInS2 thin films are having crystallites of size of ∼1–3 μm. Thin film of ZnSe was electrodeposited on CuInS2 film in order to fabricate a solar cell. CV and photovoltaic characteristics established the formation of the CuInS2/ZnSe heterojunction.