UV-Enhanced nonlinear optoelectronic features in iridium-doped tin oxide thin films

This work explores the influence of UV light on the third-order nonlinear optical (NLO) properties of iridium-doped tin oxide (Ir-doped SnO2) films prepared by spray pyrolysis. The NLO response of these films is systematically evaluated using single-beam transmittance and two-wave mixing experiments. A nanosecond laser source emitting at 532 nm induced a two-photon absorption effect positively affected by UV irradiation, resulting in a significant improvement in the NLO properties of the Ir-doped SnO2 films. A reliable and reproducible deposition route was employed to effectively control the film thickness. The effect of Ir doping on SnO2 semiconductor thin films was meticulously characterized using various analytical methods, including scanning electron microscopy, energy dispersive spectroscopy, x-ray photoelectron spectroscopy, and x-ray diffraction analysis. Optical properties such as refractive index, extinction coefficient and thickness were investigated using ultraviolet-visible and spectroscopic ellipsometry. Additionally, the electrochemical impedance spectroscopy measurements revealed distinct optoelectronic behavior induced by an UV light source. The observed strong NLO response exhibited by the Ir-doped SnO2 thin films holds great interest for potential applications in photonic and nonlinear devices.