The Preparation Of Vanadium Dioxide Thin Films And Their Application In The Terahertz Devices

It is known that vanadium dioxide undergoes a remarkble, thermally induced, reversible semiconductor-to-metal phase transition around68℃, resulting in great changes in its resistivity, magnetic permeability and optical properties. This kind of change of optical and electrical properties has been widely used in many fields, Recently, the application of VO2film in the terahertz band received extensive attention.Terahertz is a special period of the electromagnetic spectrum between microwave and infrared. Terahertz known as the science and technology basis of the next generation of Information Industry in the international arena, its unique superiority has been understood generally. We have to provide terahertz functional devices to promote the practical application of terahertz technologies. However, unlike the microwave and optical bands, the natural materials lack of effective response to the terahertz band, the existing electronic devices and optical devices can not achieve the terahertz transmission and control. The development of teraherz materials and devices has become one of the key issues to be solved by the terahertz field. In this context, this thesis proposed a way that combined the phase change materials and metamaterials to design and develop practical terahertz function device.In this thesis, we deposited high-quality VO2films by r-f reactive magnetron sputtering on glass substrates. And various properties of VO2films to be analyzed meticulous by four-probe resistance tester, X-ray diffraction (xrd), and atomic force microscopy (afm). And discussed the effects of partial pressure of oxygen, sputtering temperature and sputtering power in the magnetron sputtering process Finally we got the optimum preparation process parameters of the vanadium dioxide films,and prepared high-quality VO2thin films which conductivity can change for3-4orders.Metamaterial is an artificial electromagnetic composite structures or composite materials with the extraordinary nature which cannot find in natural materials.In this thesis, we combined pre-prepared VO2films and metamaterials, simulated firstly,and then prepared specific devices of terahertz amplitude modulator and switch-mode terahertz absorber using magnetron sputtering and lithography. Finally,we tested the performance of devices by Terahertz time-domain spectroscopy. The absorption range of Terahertz absorption can adsjusted between40%-80%,and the amplitude modulation of the Terahertz modulator is more than70%.This thesis shows the great potential applications of the VO2films in the terahertz functional device.