VO₂ Thin Film Based Electro-optic Switching

Vanadium dioxide is a kind of metallic compound which undergoes a reversible semiconductor-metal phase transition near 68℃. The phase transition is accompanied by significant changes in optical and electrical properties. For the characteristics that its phase transition temperature is near to room temperature and its optical electrical performance have changed much during phase transition, VO2 has a great deal of potential applications. In addition, VO2 is a purely electronic Mott–Hubbard transition material, which phase transition can be similarly induced by adding more electron. So we can use electric field to change the phase estate of the material. In the same time, the physics state of the material is changed and the electro-optic switch purpose is achieved.In the thesis, VO2 thin films are deposited on the silicon substrate by magnetron sputtering by different technics conditions. The composition, microstructure, surface shape and optics properties of VO2 thin films are studied with XRD, XPS, SEM, Raman dispersion spectrum apparatus. The best technics condition to produce VO2 thin film is found out.VO2 thin film based electric-optical switching is made by lithography and etching process. Under the control of electric fields, the phase transition character of the device is tested by Raman dispersion spectrum apparatus, and the switching character is tested by FTIR. It is found out that above 4V, phase transition appears in VO2 thin film, and the reflectance of the device increases sharply. The switching ability is fulfilled.