Abstract
NiO nanoparticles (NPs) were prepared by microwave irradiation technique. The resulted NiO NPs were affirmed during chemical precipitation by thermal analysis and X-ray diffraction (XRD) characterization. XRD showed five distinguishable peaks of NiO. The nano-NiO films were fabricated by drop solution, while the films were irradiated by UV light at different exposure periods of 0, 1, 3, and 5 h. The crystalline size of nano-NiO films was decreased from 27 to 16 nm by UV irradiation process. On the other hand, the conductivity of nano-NiO films has been observed to be increased under the effect of UV irradiation. Also, the optical constants were calculated in the range of 300-2500 nm. The mechanism of the electronic transition of the present sample was characterized by the direct allowed transition, whereas the band energy gap of the as-deposited was evaluated to be 3.81 eV and declined to 2.93 eV for the UV-irradiated film exposed to the UV rays for 5 h. However, the calculated non-linear optical parameters have been found to increase as the irradiation time exposure increases.