Influence of total absorbed dose of Co-60 γ-radiation on the properties of h-MoO3 thin films

Optoelectronic and photonic devices are confronted with challenges imposed by extreme environmental conditions encountered in applications such as space satellite, nuclear radiation environment, etc. High energy radiations may alter the physical characteristics of these devices. In this context, studying the effect of gamma (gamma) radiation on relevant semiconductor thin films for devices is of paramount importance to ensure its optimum performances. In this research, the effect of high energy gamma-radiation (with doses 50 kGy, 150 kGy and 250 kGy) on the properties of hexagonal molybdenum trioxide (h-MoO3) thin films was thoroughly investigated. The enhanced crystallinity of the as-synthesized thin films was observed due to the reduction of defects and disorders. Interestingly, the identified hexagonal phase of the pristine film remained identical after high dose irradiation. Field Emission Scanning Electron Microscopy (FESEM) revealed no significant changes in surface morphologies of the films after irradiation. Fourier transforms infrared (FTIR) spectra confirmed the hexagonal structure of MoO3 films evidently before and after irradiation, although the peak intensities and wavenumbers were found to vary slightly. With increasing gamma-irradiation the band gap was shown to reduce from 2.92 to 2.84 eV as measured by UV-Vis-NIR diffuse reflectance spectrophotometer. The gamma-irradiation has displayed a significant improvement in the degree of crystallinity and reduced the optical band gap without transforming the hexagonal phase of pristine nanocrystalline h-MoO3 film.