Temperature-controlled switching of plasmonic response in gallium core–shell nanoparticles

Abstract

Active plasmonics is a recent area of advancement in decade-old plasmonic technology. The plasmonic response is the function of material optical properties and dimensions, which is fixed after the fabrication, so to actively tune the plasmonic resonance external agent is needed. This work studies a gallium core-shell nanoparticle (NP) spherical structure with a native oxide shell of a few nanometers followed by a shell of liquid and core of solid. The dimension of phases in a NP can be reversibly controlled by varying temperature providing the ability to switch the plasmonic response. The results show a monotonous decrease in extinction cross-section at the resonances as liquid shell size decreases, and lossy core increases providing a new pathway for the control over optical properties of the system. This work explores the phase-change plasmonics in Ga NP which is chemically stable material especially in UV where gold and silver are lossy and Al is chemically unstable. Perspectives of the approach for thermal sensors and temperature-dependent plasmonic switches are discussed.