Preparation And Properties Research Of The Multilayer Doped Vanadium Dioxide Thin Film

Vanadium dioxide（VO₂）has a representative metal insulation phase transition performance,which has attracted much attention in many vanadium oxides.The phase transition temperature of VO₂ is about 341k,and the phase transformation process is accompanied with the change of crystal structure,which will bring about the reversible mutations of vanadium dioxide in electricity and optics.These characteristics enable VO₂to be used in rich applications,including construction,electronics,information materials and other aspects.However,the applications of VO₂ need to meet various practical conditions.The key problem is to regulate the phase transition temperature of VO₂.Ions doping is one of the most efficient methods,but which has two sides.Although it can effectively control the phase transition temperature of VO₂,it will destroy the optical properties.In order to improve the optical properties of VO₂ thin film,the researchers prepared composite films with sandwich structure by adding buffer layer and antireflection layer,but the phase transition temperature of the composite films is higher.Because the method including many materials,and the preparation process is complex and costly,it is not conducive to the large-scale production and application of VO₂ thin film.Therefore,it’s an urgent task to effectively regulate the phase transition temperature of VO₂,and abate the harmful effects of ions doping,raising optical properties,promoting the practical application of VO₂ thin film.In this paper,we choose tungsten element to dope,using polymer assisted deposition method（PAD）to prepare the thin film,and study the electrical and optical properties of multilayer doped VO₂ thin film.In order to improve the optical properties which was destroyed by ions doping,the doping layer and undoped layer were selected to grow alternately,and the multilayer doped VO₂ films with vertical stacking structure were prepared to explore the influence of tungsten and layer structure.The main contents include:（1）Based on the previous experiments,the doping layer and undoped layer of tungsten ions were grown alternately to prepare the vertical stacking structure of multilayer doped VO₂ thin film;（2）XRD,XPS,SEM and temperature dependent Raman spectroscopy measuring technologies were used to characterize the films.The effects of tungsten doping and layer structure changes on the crystal structure,element composition and surface morphology of VO₂ were investigated.（3）Van Der Burger method was used to test the electrical properties of the multilayer doped VO₂ thin film.The effects of tungsten concentration on the phase transition temperature,the resistance ratio and the width of thermal hysteresis loop were investigated.The mechanism of tungsten ion doping changing the properties of vanadium dioxide was analyzed.（4）The transmittance of the films in the visible and near infrared band was measured,and the influence of ions doping and layer structure on the optical properties of the VO₂ films was further explored.