Surface plasmon resonance tunability in VO₂/Au/VO₂ thermochromic structure

Nanometal-VO₂ composite systems can exhibit a reversibly tunable localized surface plasmon effect under external temperature stimuli due to the temperature-sensitive dielectric function of the thermochromic VO₂ thin film. In order to improve the tunability range and enhance the resonance shift magnitude (Δλ_SPR), the VO₂/Au/VO₂ sandwich structure was deliberately designed here. The plasmonic and thermochromic characteristics of this structure were powerfully dependent on the gold deposition time (t). By varying this parameter, the resonance wavelength (λ_SPR) of the semiconductor phase can be regulated from the visible range (686 nm) to the near-infrared range (1482 nm) and a maximum Δλ_SPR of 714 nm can be achieved at t = 3.5 min. This study may provide insights into plasmonic noble metal nanoparticles on a thermochromic VO₂ matrix and offer potential applications in temperature-sensitive nanodevices.