Vanadium Oxide Thin Film Preparation Process And Performance Research

This paper introduced that the properties of V and vanadium oxide especially V2O5 and VO2,its preparation,especially sol-gel method and application.VO2 undergoes a semiconductor to metal phase transition at approximately 68℃with abrupt change in electro-optical property, and it can be widely used in thermal, electrical switching elements and optical storage media devices. The film of therm ally-oxidized V is a mixture of different oxides with variable valences such as VO,V2O3,VO2,V2O5,It is difficult to get pure VO2. Much work has been done to investigate the optical and electrical properties and numerous methods are used to prepare thin film of VO2. Single-crystal VO2 have good electrical and optical properties. its resistance rate will have 5 magnitude changes when the temperature change 0.1℃. But because of its large-expansion coefficient, after the phase-change will lead to the breakdown of single-crystal and phase transition process irreversible.So In this paper, Vanadium oxides thin films were prepared by the method of inorganic sol-gel from V2O5 (AR).V2O5 xeroge films were prepared on Si substrates from V2O5 sol with dip-coating and drop-coating technique, and heated in the air to prepare V2O5 thin films with certain optimization orientated. The investigations from XRD and microstructure observation reveal that the preferred orientation has relation to heat treatment temperature, the higher the heat treatment temperature, the more merit-based growth the V2O5 thin film will have.Using prepared orientation V2O5 thin films prepare VO2 thin films by vacuum annealing process. VO2 thin films were prepared by V2O5 thin films on glass substrates. The experiment conclusion suggest that the better vacuum annealing process is under 470℃～480℃continued 2h. With this process single-phase VO2 films growing along with <110> Orientation were prepared. Microstructure analysis shows that the surface quality of thin film is good, grain size and distribution is Uniform.R-T curves of the thin film samples were determined, and X-ray photoelectron spectroscopy.The R-T curves shows that the single-phase VO2 films growing along with <110> Orientation has semiconductor properties, that is, the resistance is down with temperature up, there is no significant resistance mutations,in temperature range (295K-350K). XPS analysis showed that the vacuum annealing process achieve a true that V5+ be changed to V4+. The peak of V2p3 move to the low-energy and the peak of Ols move to the high-energy moves with the vacuum annealing temperature increase.The properties of Vanadium oxide thin film made a preliminary exploration study,we found that The thin film sample was dried in 300℃,heated in 450℃/1h and vacuum annealing in 470℃/2h, will be able to occur phase transition in 290K, less than VO2 single crystal phase transition temperature of 51K, at the same time its electrical and optical properties has been changed. Through the XPS and XRD analysis we found that vanadium oxide film is not a single-phase but it is a mixed valence main with low valence vanadium oxide.