Evolution of polymorph and photoelectric properties of VO2 thin films with substrate temperature

Abstract

For specific application, direct deposition of high quality VO2 films on common glass substrates is potentially promising and the work for controllable preparation of VO2 films with different polymorphs is desirable. This work reports controllable preparation of VO2 films with different polymorphs (B and M) optimizing physical and thermochromic properties of VO2 thin films on amorphous glass via controlling the substrate temperature. By adjusting the substrate temperature, B-VO2 films which can be formed at a relatively low temperature (400 °C) possesses a comfortable sheet resistance and the value of temperature coefficient of resistance (TCR) is about 2.4%/K; M − VO2 thin films are successfully prepared when the substrate temperature is higher than 400 °C. It is found that the optimized VO2 (M) thin film grown at 500 °C has a favorable property such as ∼3 orders of magnitude change in sheet resistance during phase transition, high luminous transmittance of more than 62%, a solar switching efficiency of ∼7.5% and a Near-Infrared-Region switching efficiency of 52.4%. Our experimental results can provide technical supports for the practical application of VO2 thin films.