Asynchronous-pulse ultrasonic spray pyrolysis deposition of CuxS (x=1, 2) thin films

Nanocrystalline CuxS (x=1, 2) thin films were deposited by asynchronous-pulse ultrasonic spray pyrolysis (APUSP) technique on glass from CuCl2 and thiourea at relatively low temperature without any complexing agent. The deposited films chemically close to CuS were found to be polycrystalline phases, while the Cu2S films were a mixture of amorphous and polycrystalline as well. The crystalline phase of particles was highly depended on the molar ratio of thiourea to CuCl2 and the pyrolysis temperature. The growth of CuxS thin films was controlled successfully by the improved APUSP method. Characterization of the films has been carried out using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. XRD and XPS analysis showed stoichiometric CuxS (covellite CuS and chalcolite Cu2S). Raman shifts of the films were measured at 474 cm−1 (CuS) and 472 cm−1 (Cu2S).