Research On Preparation And Properties Of Vanadium Oxide Thin Films With Low-cost Vanadium Buffer Layer

Vanadium dioxide?VO₂? films have good phase transition performance and are widely used in commercial applications such as switching modulation,tunable filtering,and sensors.At the temperature below the phase transition temperature,the VO₂ film is an insulating or semiconducting phase with high resistance and high light transmission,but as the temperature rises beyond the phase transition temperature,the VO₂ film will quickly become the metal phase,and the resistance decreases by orders of magnitude.At present,the study of vanadium oxide phase transition is mainly based on heat,electricity and light.Through these induced signals,it is placed in two different states of insulation and metal to realize the function of modulation and switching.As a modulation switch device,the VO₂ film should satisfy:a large phase change amplitude,a low phase transition temperature,and a small loop width.The majority of scholars reach the requirements through doping,buffer layer and other means,but doping will destroy the vanadium oxide structure,and have lower phase transformation amplitude,by sacrificing the phase change amplitude to achieve the corresponding purpose,and the buffer layer means more than one complex processes such as atomic layer deposition,pulsed laser methods,etc.Therefore,this thesis focuses on the integrated preparation of buffer layer and vanadium oxide film,and optimizes the phase transformation performance of vanadium oxide through the low-cost vanadium buffer layer.The following four parts are carried out:?1?It is studied that different buffer layers have an optimized effect on the phase transition characteristics of vanadium oxide thin films.The flow rate of argon oxygen flow during sputtering is 98:0.5.The highest content of V³⁺ in the buffer layer reaches84.6%.The phase change gain is the largest,the phase transition amplitude is 819,the phase transition temperature is 58.2?,and the return line width is 10.3?.?2?As the thickness of the buffer layer increases,the phase change amplitude of the film decreases,and the width of the loop decreases,but the width of the loop width narrows as the thickness of the buffer layer increases.When the buffer layer has a thickness of 20 nm,the return line width is only 5.4?,the phase transition amplitude is 423,and the phase transition temperature is 53.2?.?3?In the absence of a buffer layer,the 30 nm thick vanadium oxide film prepared at an annealing temperature of 350? has no phase change characteristics,and under the same conditions,the vanadium oxide film prepared by the buffer layer has a phase transition.characteristic.In addition,the effect of different oxygen content on the properties of vanadium oxide film at 350? annealing temperature was also studied.It was found that the phase change property first increased and then decreased.When the argon oxygen flow ratio was 98:4,the most obtained was obtained.The excellent vanadium oxide film has a phase transition amplitude of 491,a loop width of 6.8? and a phase transition temperature of 53.5?.?4?In the study of optical modulation applications,it was found that the vanadium oxide film of the buffer layer has higher optical modulation capability than the vanadium oxide film without the buffer layer,and the return line width is narrower and the phase transition temperature is lower.Among them,the argon-oxygen flow ratio is 98:0.4 when sputtering the buffer layer,and the argon-oxygen flow ratio is 98:1 when sputtering vanadium oxide.The optical properties of the composite film annealed at 400? are preferably 76.2%,and the phase transition temperature is 56.23?.The line width is 8.17?.