The influence of γ-doses irradiation on structural and optical properties of NiO thinfilms prepared by Spin coating method

We report a new green synthesized nanostructured thin films of Nickel oxide (NiO) prepared
using spin coating method. The samples were irradiated at different γ-doses by Co-60
radioisotope. The obtained films were characterized using X-ray diffraction (XRD), scanning
electron microscopy (SEM), 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 demonstrate that the asdeposited NiO samples show a cubic structure with (111) preferred orientation common at
all gamma radiation doses. Raman spectroscopy of the nanocoating show the presence of
three strong Raman active peaks corresponding to 2TO, 2LO, and 2M emerged from Ni-O
super exchange mechanism implying the presence of defect-rich NiO thin film. The
formation of uniformly distributed nanospheres like structure NiO thin films with an average
grain size increased with increasing the γ ray dose irradiation was confirmed from SEM. The
optical energy gaps of the samples were found to decrease when increasing the γ ray dose,
the Eg value decreases from 3.65 eV for as deposited NiO thin film to 3.40 eV for sample
irradiated at 50 kGy.