The Research On Fabrication And Gas Sensitivity Performance Of Noble Metal-decorated Vanadium Dioxide Nanowires

Nitrogen dioxide?NO₂?is a kind of toxic gas,a small amount of NO₂ can cause diseases such as respiratory tract infection,so it is necessary to develop a gas sensor with higher sensitivity to detect NO₂.Metal oxide semiconductor materials have the advantage of high sensitivity and good stability,are widely used in the detection of NO₂,however,the higher operating temperature limits its further development.As a new type of metal oxide semiconductor material,vanadium dioxide?VO₂?can detect NO₂ at room temperature,but the sensitivity of current VO₂ materials is still low.Increase the specific surface area and decoration with metal nanoparticles on the surface of metal oxides have always been used to improve the sensing ability.In this paper,VO₂ nanowires were gained by chemical vapor transport deposition method.The specific surface area of VO₂ nanowires was improved by changing the substrate and varying deposition time.The experimental results show that on the unpolished quartz substrate,the VO₂ nanowire with best surface topography can be obtained.By changing the deposition time,the nanowires with the highest density and specific surface area were obtained at 4h,it has the best sensitivity as 1.20 to 5ppm NO₂ at room temperature.In order to further enhance the sensitivity of VO₂ material to NO₂,we used the ion sputtering with rapid annealing method to deposited gold particles on the surface of the nanowires.By changing the sputtering time,the influence of the size and amount of gold particles on the gas sensing properties of VO₂ nanowires was investigated.It was found that the nanowires with the gold deposition time of 10 s has the largest gold particles amount and the smallest gold particle size,and has the best gas sensitivity to 5ppm NO₂ as 3.22.The temperature test shows that the gold decorated VO₂ nanowires have the highest sensitivity to NO₂ at room temperature and the sensitivity decreases when the operating temperature increases.The experimental results show that by growing VO₂ nanowires and metal decoration,the sensitivity of VO₂ material to NO₂ is successfully enhanced,which is of great significance for the study of new metal oxide semiconductor gas sensor.