Structural, morphological and optical studies of nanostructured cadmium oxide films: the role of pH

In this work, nanocrystalline cadmium oxide (CdO) films were deposited on glass substrates for various pH values ranging from 11.3 to 12.5 by successive ionic layer adsorption and reaction (SILAR) technique. To obtain good film stoichiometry, the annealing of films in static air at a temperature of 623 K for 1 h was carried out. The comparison of structural, morphological and optical properties of CdO films at different pH of the solution has been studied. The effects of pH on the crystal structures, the orientation of crystallization and crystallite sizes i.e., structural properties of the films were analyzed with X-ray diffraction (XRD). XRD analysis revealed the polycrystalline nature of the CdO films with cubic structure and show preferential orientation along (111) and (200) planes. The surface morphology of the prepared films having different pH values was investigated by scanning electron microscope (SEM). The optical band gap of nanocrystalline CdO films at different pH has been measured using Ultraviolet–Visible (UV–Vis) spectroscopy. The optical properties showed that a significant reduction in the optical band gap is observed from 3.26 to 2.35 eV by increasing the pH value of the solutions from 11.3 to 12.5, respectively.