The Study On Fabrication, Phase Transition Regulation Of VO₂ Microstructures And Their Application In Photodetectors

In recent years,with the continuous development of digital information industry and the vigorous promotion of intelligent equipment,semiconductor manufacturing and integrated circuit industry have developed rapidly,pushing the traditional silicon-based semiconductor technology to the peak,and the density of electronic components on semiconductor chips has increased rapidly.However,as the characteristic size of traditional silicon-based components gradually approaches the physical limit,it also brings many technical problems,such as short channel effect,large leakage current and power consumption,leakage induced barrier reduction effect,weak control ability of gate to channel area and so on,which seriously restricts the further development of semiconductor technology.In order to solve these problems,on the one hand,researchers optimize or redesign the structure of devices and improve the preparation process on the existing basis to alleviate the contradictions and bottlenecks faced in the development of semiconductor technology industry;On the other hand,we are also trying to develop new and high-performance semiconductor materials to partially or completely replace the current silicon-based semiconductors.Among them,metal oxide materials with metal insulator transition（MIT）,especially vanadium dioxide（VO₂）,whose phase transition temperature is closest to room temperature,have great and rapid changes in physical properties such as resistivity and optical transmittance before and after phase transition,which makes VO₂materials in electrical switches,smart windows Photodetectors and memory devices show great application prospects.In this context,this paper focuses on the preparation,phase transformation regulation and photoelectric detection of VO₂,a typical phase change material.The specific contents include the following:（1）High quality VO₂microstructures,including two-dimensional VO₂thin films and one-dimensional VO₂microwires,were successfully prepared on 500 nm Si O₂/Si substrate by a simple and effective vapor solid method with vanadium pentoxide（V₂O₅）powder as precursor,and their growth mechanism was systematically studied.（2）The electrical phase transition characteristics of VO₂thin films and microwires were studied.Among them,the phase transition temperature of VO₂thin films is about 340K,and four VO₂thin films with different single crystal microplate sizes are prepared by modulation the amount of precursor.The magnitude of the change of the resistivity of the thin films is directly proportional to the average size of the microplate,and the change of the resistivity can reach up to 4.2 orders of magnitude.The phase transition temperature of the prepared VO₂microwires is 416 K.The higher phase transition temperature is mainly due to the ghost and the stress effect of the substrate.The effect of plasma bombardment on the phase transition characteristics of VO₂microwires was further studied.The phase transition temperature of VO₂microwires was reduced to 340 K by oxygen plasma bombardment.（3）Based on the above prepared VO₂microstructure,VO₂photodetectors were prepared.The optical response characteristics of VO₂thin films under 850 nm irradiation and VO₂microwires under visible light were studied.In addition,by using laser to oxidize the surface of VO₂microwires to form VO₂/V₂O₅heterostructure,the light response of VO₂microwires under visible light is improved by two orders of magnitude.