Effects of the annealing and CdCl₂ treatment on the structural and optical properties of ammonia-free and ammonia cds thin films by chemical bath deposition

CdS thin films, with and without ammonia, were prepared using the chemical bath deposition method (CBD), with bath temperature of 70°C, 20 and 60 min times of reaction and different complexing agents. We study the effects of CdCl₂ treatment and annealing on these films. The thin films were characterized by X-Ray diffraction (XRD), Scanning Electron Microscopy (SEM), optical absorption spectroscopy and Atomic Force Microscopy (AFM). The XRD measurements showed that the films have polycrystalline nature, hexagonal structure and the crystallites are oriented preferentially with the (002) and (110) planes. The optical absorption measurements show the presence of direct transition with energy band gaps of 2.55 eV and 2.44 eV and after diminished to 2.37 eV and 2.36 eV.