Gamma irradiation-induced effects on the properties of the TiO2 on fluorine-doped tin oxide prepared by atomic layer deposition

The effect of gamma irradiation with different doses (25-75 kGy) on TiO2 thin films deposited by atomic layer deposition has been studied and characterized by X-ray diffraction (XRD), photoluminescence measurements, ultraviolet-visible (UV-Vis) spectroscopy, and impedance measurements. The XRD results for the TiO2 films indicate an enhancement of crystallization after irradiation, which can be clearly observed from the increase in the peak intensities upon increasing the gamma irradiation doses. The UV-Vis spectra demonstrate a decrease in transmittance, and the band gap of the TiO2 thin films decreases with an increase in the gamma irradiation doses. The Nyquist plots reveal that the overall charge-transfer resistance increases upon increasing the gamma irradiation doses. The equivalent circuit, series resistance, contact resistance, and interface capacitance are measured by simulation using Z-view software. The present work demonstrates that gamma irradiation-induced defects play a major role in the modification of the structural, electrical, and optical properties of the TiO2 thin films.