Photoelectric response of ITO films under UV irradiation

This article presents the results of a study of photoinduced processes occurring in thin indium tin oxide (ITO) films irradiated with ultraviolet (UV) radiation. For the study, ITO films were deposited on glass substrates using reactive magnetron sputtering under different process conditions, which allowed them to achieve distinctly different initial concentrations of oxygen vacancies and, consequently, conduction electrons. Monitoring the resistance of the prepared ITO samples upon UV irradiation revealed a decrease caused by the generation of additional charge carriers due to the breakdown of chemical bonds with gas atoms adsorbed on the film surface. Polycrystalline ITO films with a low initial charge carrier concentration exhibit the greatest sensitivity to UV irradiation. Furthermore, it is shown that the generation of additional charge carriers in ITO is also due to the thermal ionization of tin impurity atoms. Furthermore, when Al/ITO/Al thin-film structures were irradiated with UV radiation, an increase in the potential difference was recorded on the metal contact pads. The conducted studies of the photoelectric response of ITO films exposed to UV radiation demonstrate the potential for their use as a sensitive layer in a UV detector.