Highly orientated V2O5 thin film was prepared by sol-gel method on SiO2/Si substrate. When baked at temperature higher than 400°C and pressure lower than 2Pa, the V2O5 thin film can be converted to VO2 thin film. Annealing V2O5 thin film under 1-2Pa, 480°C for 20 minutes, the VO2 polycrystalline thin film with resistance change larger than 3 orders of magnitude and 6.2°C hysteresis width was obtained. Meanwhile the transition progress from V2O5 to VO2 was discussed in detail. It was observed that the valence of V was reduced by the sequence as V2O5 to V3O7 to V4O9 to V6O13 to VO2, namely from VnO2n+1(n=2,3,4,6) to VO2. It was confirmed that the key factors to obtain VO2 thin film with good switching property were the conditions of pre-heating and vacuum baking for V2O5 thin film.
|