Effect of Ar:O2 gas atmosphere on optical properties of Y2O3-doped ZnO thin films by RF sputtering

Abstract

In this work, the radio frequency magnetron sputtering technique (RF sputtering) was utilized for the deposition of Y2O3-doped zinc oxide (ZnO) thin films on a SiO2 substrate. The microstructures and optical properties of the thin films deposited utilizing various gas (Ar:O2) ratios at 400 C were characterized. XRD investigation of thin films demonstrates that all deposited films are polycrystalline and there is a single phase hexagonal wurtzite type structure with a strong (002) orientation. An increment of O2 in the gas mixture reduces the intensity of peak (002). Y2O3-doped ZnO thin films exhibited denser morphology with refined microstructure as compared to pure ZnO films. The absorbance and transmittance of doped ZnO thin films were measured by UV-VIS-IR spectrophotometer in the wavelength range 300 nm to 800 nm. High transmittance in the visible region and high band gap of films were revealed. Photoluminescence (PL) of films was estimated at the excitation wavelength of 325 nm and it uncovered two PL peaks present in UV and visible regions (400 nm to 445 nm). The effect of Ar:O2 gas proportion on stoichiometry, structural and optical properties of the Y2O3-doped ZnO thin films was also revealed.