Metal-insulator phase transition in vanadium oxides films

Vanadium oxide films (VO₂) are of a typical phase transition ranging between metal phase to a semi-conducting phase. The theoretical metamorphose temperature of VO₂ is around 340K (67°C). This transition temperature is mostly governed by the deposition method in which the film was made, and the film's composition. Optical and electrical properties of VO₂ films are dramatically changed during this phase transition, thus making it useful in many microelectronics and optoelectronics applications. In this work we evaluate several deposition methods of VO₂ and their relations to the electro-optics properties of such films. The examined VO₂ films consisted of various phases of the material. Best films to demonstrate a metal-insulator transition were made in vacuum evaporation of V powder in a tungsten boat, treated in argon-oxygen flow (10:1), at 400°C. The temperature range of phase transitions was found at 16-80°C. Resistivity changes and colors of the films were studied as well.