Exploring the Role of pH on the Physical and Optoelectronic Attributes of Nanostructured NiO Thin Films

In this study, nanostructured nickel oxide (NiO) transparent conductive thin films have been deposited onto glass substrates by utilizing the successive ionic layer adsorption and reaction (SILAR) technique at different pH values. The impact of pH on the structural and morphological characteristics of the NiO thin films was analyzed using powder X-ray diffraction (XRD) and scanning electron microscope (SEM) while the optical characteristics of the NiO thin films were examined using Ultraviolet/Visible (UV-Vis) spectroscopy. XRD studies showed that all the films were polycrystalline with cubic structure and indicated (111) and (200) preferred orientations. SEM images revealed a compact deposition and worm-like surface morphology. The optical studies indicated that the NiO thin films had an average optical transmittance of similar to 83% and the optical energy band gap values varied from 3.50 to 3.38 eV for pH solutions of 11.0 and 12.0, respectively. The effect of pH on the film thickness and grain size was also investigated. The results of these investigations demonstrated that the variation in pH has a notable impact on the physical and optical features of SILAR deposited NiO thin films.