Phase Transition Properties Of Vanadium Dioxide Films Prepared By Thermal Oxidation

In this paper, VO2 thin films were taken as the study objects and fabricated by thermal oxidation in air or oxygen from the metallic V films which were deposited on the normal glass, quartz substrate and SiO2/Si(100) substrate by magnetron sputtering. The effects of thermal oxidation temperature on the microstructure, optical transmittance, phase transition temperature and composition of the VO2 thin films were investigated by XRD, AFM, FT-IR, XPS (X-ray photoelectron spectroscopy) and Ultraviolet-visible spectrophotometer respectively. The results are as follows:1. VO2 thin films which have phase transition property were prepared from metallic V films of 300nm on the normal glass after oxidized at 400℃and 450℃for 1h in air. The phase transition temperature of the sample which oxidized at 400℃is about 50℃with a thermal lag of 10℃approximately, its IR transmittance tends to zero when the testing temperature is more than 60℃.2. Metallic V films of different thickness on the normal glass were thermally oxidized in oxygen. When the film thickness is thicker, VO2 thin film can be fabricated from the wider oxidization temperature and its phase transition property is relatively better.3. Metallic V films on the quartz glass and SiO2/Si(100) substrate were thermally oxidized in air. VO2 films prepared on the quartz glass perform phase transition property, however, on SiO2/Si (100) substrates, the phase transition phenomenon doesn't happen at the same conditions. The metallic V films on the quartz glass were thermally oxidized at 400℃in air, its phase transition temperature is about 60℃with a thermal lag about16℃, its IR transmittance variation almost ups to 50% and its visible transmittance is closing to 40%.