Preparation and phase transition properties of Ti-doped VO2 films by sol–gel process

Abstract

Pure and Ti-doped vanadium dioxide (VO2) thin films were deposited on muscovite substrates using an inorganic sol–gel method. The crystallinity, stoichiometry, surface morphology and phase transition properties of the films were investigated using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and in situ FTIR measurement, respectively. The results indicated that all the VO2 films exhibited polycrystalline structure, with a (011) preferred orientation. But Ti doping affected the morphology of the films remarkably, which then led to varied phase transition properties. Particularly, the phase transition temperature elevated by increasing the doping concentration of Ti (from 61 °C for pure film to 71.5 °C for the film doped with 2.8 at.% Ti), and the hysteresis loop decreased simultaneously. This study proposed a new method to prepare Ti-doped VO2 film and provided considerable insights for the application of Ti-doped VO2 film due to its unique phase transition properties.