Effects of postdeposition annealing on the metal–insulator transition of VO₂₋ _x thin films prepared by RF magnetron sputtering

Abstract

We report the fabrication of textured VO 2− x films on c -cut sapphire substrates by postdeposition annealing of V 2 O 3 films prepared by RF magnetron sputtering using V 2 O 3 as the target. Although the prepared VO 2− x films are expected to be oxygen-deficient, overoxidation on the film surface was revealed by X-ray photoelectron spectroscopy. The metal–insulator transition (MIT) characteristics of the VO 2− x films were investigated. MIT parameters including the transition temperature, transition sharpness, and hysteresis width of the VO 2− x films were manipulated by varying the oxygen pressure during postdeposition annealing. The suppression of optical transmittance in the near-infrared region was observed by increasing the temperature through the MIT.