Morphological and Optical Properties of CdS Nano-Crystalline Thin Films by Chemical Bath Deposition

CdS thin films were prepared by chemical bath deposition (CBD) at different ammonia concentration and different temperature using cadmium chloride hydrate, thiourea, ammonium chloride, ammonia and deionized water as precursors. The morphology structure and the optical properties of CdS thin films were characterized by scanning electron microscope (SEM), ultraviolet-visible spectra and spectroscopic ellipsometry. The results indicated that CdS thin film could be grown when ammonia concentration at the range of 0.4-1.0 mol /L and in the temperature range of 50 °C -80 °C. Within 600-980 nm wavelength，the average value of the refractive index was found to be 1.70 and the extinction coefficient was less than 0.08.