Preparation Of Vanadium Dioxide Thin Films And The Research On Terahertz Modulation

THz(Terahertz, THz) is an electromagnetic radiation which usually refers to the frequency range within 0.1THz-10 THz in the transition area of macro- electronics and micro-photonics. THz has a lot of important applications, such as wireless communication, radar imaging, detection of substances, and medical diagnosis. Promoting the practical application of terahertz science needs to provide good THz functional devices, such as terahertz modulators, switches, filters, amplifiers and so on. Since high-frequency electronic devices and optical device applications bring a serious deterioration in the THz, research on electronic functional materials and functional devices will be very important. In this context, we combinate of the VO2 film and metamaterial, and simulate, design and develop THz modulator device.This thesis explores the process parameters of good performance VO2 films prepared by RF magnetron sputtering. Using X-ray diffraction analyzer, scanning electron microscopy, and four-point probe resistivity test platform, we analyze the film microstructure and electrical performance, focusing on the oxygen partial pressure and substrate temperature influence on the growth of the film. Experimental test analysis shows that the film properties are very sensitive to oxygen partial pressure and substrate temperature. We prepared a resistance mutations over three orders of magnitude behaving superior performance VO2 by optimizing process parameters, whicn is critical for the development of THz devices.Then study on the effect of buffer layer thickness and the oxygen partial pressure on the growth VO2 thin film transistor structure, microstructure and properties of MIT performance on Pt metal films. Test results show the thickness of the SiO2 buffer layer can alleviate the stress between VO2 between and metal film stress. At the right of the oxygen partial pressure, high quality of VO2 film bebaving significant( 011) preferred orientation will be grown. The change in resistance is over three orders of magnitude, and the film has uniform distribution of the grains with smooth and dense surface. We apply voltage on the film observing significant jump ladder current and a current hysteresis loop, confirming the phenonmenent of VO2 film electroluminescent phase transition, which is significant in the preparation of the new electronically controlled THz devices.Finally we use CST 2012 software to simulate, design and optimizate the THz modulation device based VO2 films. Combining VO2 film and metamaterial structure, we design the THz modulation devices and test the terahertz time-domain spectroscopy. The results show that the VO2 film has the significant the effect on the THz modulation devices, and the modulation depth reaching more than 50% in the 0.62 THz, which is important in the THz communication system.