Influence of bias voltage on microstructure and phase transition properties of VO₂ thin film synthesized by HiPIMS

VO₂ thin films were prepared on quartz glass substrates by using high power impulse magnetron sputtering with different pulsed bias voltages. X-ray diffraction patterns revealed that all as-deposited films were polycrystalline monoclinic VO₂ and the preferred crystalline orientation of the as-deposited films varied with the magnitude of the bias voltage. Scanning electron microscopy images exhibited that the crystalline size of the VO₂ thin films reduced with the magnitude of the bias voltage. X-ray photoelectron spectroscopy results revealed that oxygen vacancies were formed in all films and their quantities were similar. UV–visible-near IR spectra of the VO₂ thin films at different temperatures confirmed that all films possessed typical metal–insulator transition properties. Four-point probes resistivity results exhibited that the phase transition temperature was reduced from 54 to 31.5°C when the magnitude of the bias voltage was increased from − 50 to − 250 V.