Preparation And Investigation Of Composite Structure Of Au Triangle Particles Array/VO₂ With Plasmon Resonance

Vanadium dioxide?VO₂?exhibits a metal-semiconductor transition?MST?when under the stimulation such as heat,light,electric.Obvious changes in the electrical,optical and magnetic properties could occur in the process of phase transition.So VO₂can be used to prepare pyroelectric infrared sensor,smart windows,optical switch,etc.The Localized surface plasmon resonance?LSPR?properties of Au triangle nanoparticle have been widely studied.Researches have shown that triangle nanoparticle has strong induced electromagnetic field and is more sensitive to dielectric environment compared to disk or spherical nanoparticles.So,triangle nanoparticle is a superior shape to LSPR sensor.The LSPR features of noble metal nanoparticles is not only related to the shape and size of noble metal nanoparticles but alsocloselyrelatedtodielectricenvironmentsurroundingnanoparticles.Therefore,utilization of the changed dielectric constant before and after phase transition to modulate LSPR properties of metal nanoparticles has become a research hotspot.The research content of this paper is divided into two parts,one is preparation of VO_x thin films and the influence of preparation parameters on the performance of the VO_x thin films;the other one is the preparation of Au triangle particles array/VO₂composite structure and carry out the research on its LSPR properties.Single variable method was used to study the effect of rapid thermal annealing time and thickness of VO_x thin films on properties of thin films.The crystalline structure,microstructure,electrical and optical characteristic of VO_x films were studied by X-ray diffraction?XRD?,atomic force microscope?AFM?and SEM,four-point probe method and FT-IR/NIR Spectrometer,respectively.It was found that the oxidation degree of thin films becomes higher with the increase of the annealing time or the thickness of VO_x thin films.The phase transition temperature can be easily tuned from 57 to 49^oC for the heating process and from 48 to 42^oC for the cooling process by controling the annealing time of rapid thermal process,respectively.The widths of the hysteresis loops can also be turned by annealing time or thickness.On the basis of the research about VO_x thin films performance,Au triangle particles array/VO₂ thin films and Au triangle particles array/VO₂ nanoparticles composite structure were fabricated and studied the influence of rapid thermal annealing time and thickness of VO_x thin films on LSPR properties of composite structure.The resonance peak of Au triangle particles array/VO₂ thin films composite structure has a red shift with the increase of annealing time or thickness at room temperature.Interestingly,the resonance peak of Au triangle particles array/VO₂nanoparticles composite structure has a blue shift with the increase of annealing time.We infer that the LSPR properties of VO₂ nanoparticles have some influence on the composite structure;The resonance peak intensity of two kinds of structures is changed before and after phase transition.It is proved that the phase transition of VO₂has regulating effect on composite structure LSPR property.It is a pity that the position of peak is not changed due to vanadium oxide quality and spectral characteristics.The research on Au triangle particles array/VO_x composite structure has practical significance for LSPR sensor.