Gamma irradiation-induced effects on the properties of 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.