Preparation And Investigation Of Composite Structure Of Au/VO₂ Nanostructured Arrays With Plasmon Resonance

Recently,due to the reversible change in electrical,magnetic and optical properties in the phase transition,VO₂ has attracted serious concern for variety of practical applications,such as switching devices,smart windows,memory devices.Compared with films,the combination of nanoscale material features and the periodicity of the VO₂ nanostructured arrays became new hotspots of tunable resonance response for noble metals（Au）.However,for present conditions,the preparation of composite structure of Au/VO₂ nanostructured arrays was too complex with high cost and the influence factors were too many.So,to investigate the optimum parameters of preparation and to increase the success rate of the experiments,firstly,we fabricated VO₂/SiO₂ nanostructured arrays with easier preparation process and similar preparation methods.And on this basis,we fabricated Au/VO₂ nanostructured arrays to research the resonance response property.In this paper,VO₂/SiO₂ nanostructured arrays were fabricated via direct assembly of SiO₂ nanospheres and rapid thermal annealing of sputtered vanadium films.The factors which influenced the properties of the VO₂/SiO₂ nanostructured arrays were investigated such as lifting speed,annealing time and oxygen flow rate.The morphology,crystal structures and optical properties of composites were analyzed and investigated by field emission scanning electron microscope（FESEM）,X-ray diffraction（XRD）,atomic force microscope（AFM,Nanosurf easyScan2）and spectrometer.According to the results,we could get the optimum parameters of the preparation of VO₂/SiO₂ nanostructured arrays with the lifting speed of 100μm/min,sputtered time of 20 min of vanadium film,the annealing time of 110 s and the oxygen flow rate of 3slpm.Compared with planar film,VO₂@SiO₂ array with a maximum value of 77.4 % provided approximately 8.4 % relative increase at wavelength of around 2500 nm,fairly promising for smart windows.Based on the preparation of VO₂/SiO₂ nanostructured arrays,we fabricated the Au/VO₂ nanostructured array.The influence of the thickness of vanadium film and annealing time to Au/VO₂ nanostructured array were investigated.The microstructures and resonance response were analyzed.With the change of transmittance,a large contrast with temperature change was observed in all samples,indicating the phase transition of VO₂.At the same time,from the results of near infrared spectrum with the low temperature（20℃）,it could be seen that the resonance peaks P1 of all the three samples appeared at the position with the wavelength of around 900 nm;with the high temperature（90℃）,it could be seen that the resonance peaks P2 of all the three samples appeared at the position with the wavelength of around 1100 nm.With the change of refraction in the phase transition of VO₂,the wavelength showed the obvious blue-shift,which indicated that the phase transition of VO₂ nanostructured array could tune the resonance response of Au.