Study Of The Vanadium Oxide Thin Films By Magnetron Sputtering Technology

Vanadium dioxide is one of the most interesting phase transition materials depending ontemperature. It goes through a reversible thermally-induced metal-semiconductor phase changeand accompanied by an abrupt change of its optical and electrical properties at about68℃.Special reversible phase-change characteristic of VO2film indicates that it has a variety ofapplying prospects in the areas such as uncooled energy conserving building windows.The phase transition temperature can be adjusted and controlled by doping VO2. In this study,two-step process has been used. Firstly preparation of high-purity and tungsten-doped metallic Vfilms on glass by radio frequency magnetron sputtering, and then followed by heat treatment inthe annealing furnace in an air atmosphere. The film was prepared in this way. X-ray diffraction(XRD) and X-ray photoelectron spectroscopy (XPS) ascertained the crystal structure and valencestate of the thin film. The films’ surface micro-topography was investigated with Atomic forcemicroscopy (AFM). Optical transmittance and resistance were tested by Fourier transforminfrared spectrometer (FT-IR) and self-made film resistance measurement equipment.The experimental results indicate that when the sputtering time is90min, the films with goodphase-transition characteristic can be produced under the annealing temperature of400℃for2h.The phase-change temperature of the thin films without tungsten-doped is around60℃, the heatstagnation width is about15℃, the light transmission changes37%at the wavelength of2500nmand the resistance alters about two orders of magnitude. For tungsten-doped, the phase-changetemperature of the films reduces about10℃, the heat stagnation width reduces a little bit and theinfrared transmission reduces about5%, the rate of resistance mutations decreased. The Na+ofglass will diffuse into the films with the annealing temperature increasing.