Influence of deposition temperature on the properties of sprayed CuInS2 thin films

Copper indium disulfide films were deposited by chemical spray pyrolysis technique at different deposition temperatures. Deposition temperature was explored to understand how it affects the crystallography, stoichiometry, morphology, optical and electrical properties of the deposited films. The chemical composition of the films evaluated by energy dispersive X-ray spectroscopy revealed the presence of copper, indium and sulfur elements in the films. Also it was observed that films formed at higher temperatures are copper rich and also showed deficiency of sulfur. X-ray diffraction patterns showed that the sprayed CuInS2 films are polycrystalline with chalcopyrite structure and preferred orientation in the (112) direction. Atomic force microscope studies revealed significant variations in the surface morphology of the prepared films with different deposition temperature. An increase in the energy band gap was observed with increasing the deposition temperatures. The temperatures dependence of conductivity of CuInS2 thin films, determined in the temperature range of 225-400 K, showed their semiconducting behavior.