Spectroscopic Ellipsometry Characterization of Vanadium Oxide Thin Films Prepared by Pulsed DC Reactive Magnetron Sputtering

Vanadium oxide thin films were prepared by pulsed DC reactive magnetron sputtering under different duty cycles.The composition of the deposited films was determined by the X-ray photoelectron spectroscopy,and the optical properties of the films were investigated by a spectroscopic ellipsometer in the wavelength range of 300~850nm.The experimental results show that decreasing the duty cycle favors can enhance the oxidation of vanadium.And the best fitting results of the ellipsometric parametersΨandΔcan be obtained by using the Tauc-Lorentz oscillator associated with the bruggeman effective medium approximation model.The complex refractive index and transmittance of the films were determined from the fitted ellipsometric parameters.And it is found that decreasing the duty cycle will lead to a decrease in the refractive index and extinction coefficient,but an increase in the transmittance.