Effect of molar concentration on structural, morphological and optical properties of CdS thin films obtained by SILAR method

Thin films of cadmium sulphide (CdS) were deposited on a glass plate by the SILAR method for 0.05, 0.10 and 0.15 M concentrations. The structural, optical and morphological properties of the films were characterized by X-ray diffraction (XRD), energy dispersive spectrum (EDS), UV-Vis spectrometry and atomic force microscopy (AFM) techniques. The XRD patterns of the films indicated that the crystalline natured films have hexagonal phases. The energy-dispersive spectrum (EDS) analysis confirms the compositions of cadmium and sulphur in CdS films. The direct band gap values in the range 2.32-2.24 eV were observed from the transmittance studies, the results infer that the band gap energy decreases with increasing molar concentration. The AFM studies show that the film is evenly coated and has uniform grain sizes. (author)