The optical and electrical properties of W-doped VOx thin film

The thin films of W-doped VOx, were synthesized onto glass substrates using reactive DC magnetic co-sputtering deposition technique. The optimum synthetic process was obtained when the gas pressure was 2.0Pa, the ratio of O-2/Ar was 1.0:15, the sputtering powers were 120W for vanadium target and 45W for tungsten target during 30minutes, and all W-doped VOx films were annealed in nitrogen atmosphere at 450 degrees C for 2 hours. The structures of films were characterized by X-ray diffraction. The effects of W dopant on the semiconductor to metal phase transition of bare VOx were investigated with measuring the dependence of electrical resistance on temperature and the infrared transmittance spectra. Remarkably strong effects of W doping were observed on VOx films both the optical and electrical properties. The IR transmittance was decreased from 67.46% to 44.86%, while the transition temperature from monoclinic semiconductor to tetragonal metal was decreased from 68 degrees C to 48 degrees C through W-doped. In addition to, the temperature coefficient of resistance was changed from -1.48 %/ degrees C into -1.71 %/ degrees C for W-doped VOx film at corresponding transition temperature.