Localized surface plasmon resonance tunability of VO₂/Au/VO₂ composite nanotriangle sandwich array

A vanadium dioxide (VO₂) and Gold nanotriangle composite sandwich structure (VO₂/Au/VO₂) was fabricated via nanosphere lithography technique. It exhibits reversible localized surface plasmon resonance tunability through external thermal stimuli VO₂ phase transition by tuning the near-field permittivity of Au nanotriangle. Compared optical response to the Au/VO₂ (bottom Au top VO₂) and VO₂/Au (bottomVO₂ top Au) composite nanotriangle arrays, VO₂/Au/VO₂ structure shows a largest wavelength shift of 42 nm and a largest transmittance modulation of 13.2% between the hot-metallic and cold-insulating states. And the wavelength shift of Au/VO₂ nanotriangle array is larger than that of VO₂/Au array for the higher electric intensity on top surface of Au nanotriangle. The results suggest that this sandwich architecture is one path for designing a plasmonic structure with tunable resonance responses that can be tailored by varying the top and bottom phase materials properties of the hybrid structures.