Effect of deposition temperature on structural, optical and electrical properties of copper bismuth sulphide (CuBiS₂) thin films deposited by chemical bath deposition

The effect of deposition temperature on the structural, optical and electrical properties of copper bismuth sulphide (CuBiS₂) thin films deposited by chemical bath deposition onto glass substrates at different deposition temperatures (40 °C, 50 °C, 60 °C and 70 °C) for 5 hours deposition time period was investigated. The obtained films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX) and optical absorption spectra. All deposited films were polycrystalline and had an orthorhombic structure. Their grain size had changed with deposition temperature and their compositions were nearly stoichiometric. The optical band gap value was decreased from 2.44 eV to 2.33 eV with increasing the film thickness. Electrical parameters such as mobility and type of electrical conduction were determined from the Hall effect measurements. They showed that the obtained films have n-type conductivity and mobility values of the copper bismuth sulphide (CuBiS₂) films have changed with deposition temperature.