Effect of Heat and Laser Treatment on Cu 2 S Thin Film Sprayed on Polyimide Substrate

Three samples of copper sulfide Cu 2 S thin film were deposited on polyimide substrate by spray pyrolysis using deposition temperature of 400°C and deposition time of about 45 min. One of the samples was left as deposited, another was heat treated, while the third was laser treated. The structural, surface morphological, optical, mechanical, and electrical properties of the films were investigated. X-ray diffraction (XRD) analysis showed that the copper sulfide films were close to copper-rich phase (Cu 2 S). Increased crystallite size after heat and laser treatment was confirmed by XRD analysis and scanning electron microscopy. Vickers hardness measurements showed that the samples’ hardness values were enhanced with increasing crystallite size, representing an inverse Hall–Petch (H–P) effect. The calculated optical bandgap of the treated films was lower than that of the deposited film. Finally, it was found that both heat and laser treatment enhanced the physical properties of the sprayed Cu 2 S films on polyimide substrate for use in solar energy applications.