Preparations And Properties Of Doped VO_x Thin Films

The first chapter briefly describes the crystal structure, the types,applications and preparation methods of VO2 thin film.It also summarises the applicable prospects of VOx thin film as a new type of thin film materials.The second chapter describes the magnetron sputtering mechanism and technological characteristics. Both experimental techniques and prepared processes are elaborated on doped and undoped VOxthin films by DC magnetron sputtering.Chapter 3 studies the DC magnetron sputtering processes prepared VOx thin films.The influences of the annealing atmosphere, annealing temperature,annealing time, the flow ratio of O2 to Ar, working pressure, and substrate temperature on the resistance mutation of VOx thin film are studied. At the same time, AFM morphology and XRD are given. The VOx thin film has a good crystalline structure and greater resistance mutation,as well as there are lots of VO2 constituent phases,when the ratio of O2/Ar is 1.0:15, the sputtering power is 120W, the working pressure is 2.0Pa through nitrogen atmosphere annealing.Chapter 4 studies the processes of tungsten doped VOx films by the reaction of double targets sputtering.The properties of resistance mutation are studied by different sputtering power and sputtering time on the tungsten target.The resistance mutations are compared between undoped and doped tungsten VOxthin films.In chaptert 5,VOx/TiOx bilayer films were prepared by DC magnetron sputtering.The effects of the prepared processes of TiOx thin films on the structures of VOx/TiOx films and resistance mutations are studied.In chaptert 6, the changes of the optical transmittance vs. wave number on doped and undoped tungsten VOx films at room temperature and 80℃are studied. The results show that the optical transmittance of doped tungsten VOx film decreases significantly compared with the undoped VOx films.In addition to there is a decrease significantly in the optical transmittances before and after phase transformations.