Investigation of the properties of nanostructured nickel oxide NiO thin films irradiated at different γ-doses

Nanostructured thin films of Nickel oxide NiO were synthesized using spray coating method. The samples were irradiated at different γ-doses by Co-60 radioisotope. The obtained films were studied using X-ray diffraction (XRD), scanning electron microscopy, UV–visible spectrophotometry, Raman spectroscopy, photoluminescence (PL) spectroscopy and FT-IR. The experimental results demonstrated that the irradiation of NiO led to significant changes. XRD and Raman spectroscopy demonstrate that the as-deposited NiO samples show a cubic structure with (111) preferred orientation common at all gamma radiation doses. The optical energy gaps of the samples were found to decrease when increasing the γ ray dose, the Eg value decreases from 3.84 eV for as deposited NiO thin film to 3.60 eV for sample irradiated at 50 kGy. Scanning electron microscope (SEM) image of sprayed NiO films shows the high porosity and the presence of microcavities in surface of films.