Photosensing and anti-corrosion effects of spray-pyrolyzed Ni-doped ZnO thin films

In the present study, a custom-built chemical spray pyrolysis technique (CSPT) was used to deposit Ni-doped ZnO thin films on glass, steel, and ITO substrates at different dopant concentrations. Precursor solutions containing 0.01 M, 0.02 M, 0.03 M, and 0.04 M nickel carbonate, together with 0.1 M zinc acetate, were used to prepare Ni-doped ZnO thin films. The prepared films were examined for their morphological, structural, and optical characteristics. Scanning electron microscopy (SEM) revealed molarity-dependent morphology, with more uniform surface morphology at higher dopant concentrations. Energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) confirmed the presence of Ni, Zn, and O as the major elemental components of the films. UV–visible spectroscopy showed that film transmittance decreased as the dopant concentration increased. X-ray diffraction (XRD) analysis indicated that all films were polycrystalline and that the crystallite size increased with increasing Ni dopant concentration. The Ni-doped ZnO films were also coated on ITO and steel substrates for application-oriented studies. The films coated on ITO substrates were used to investigate current-voltage responses and optical sensing properties. The film prepared with 0.03 M Ni dopant exhibited more efficient photosensing behavior than the films prepared with other dopant concentrations. Similarly, the films coated on steel substrates were evaluated for anti-corrosion properties, and the results showed that the coatings protected the substrates from corrosion.