Greatly enhanced photoluminescence of an integrated WSe₂ monolayer by exploiting the pure magnetic resonance and localized strain induced by a hybrid Si/Si₃N₄/Au nanoantenna

Exploiting the optical resonances inherent to dielectric nanoparticles offers an effective approach for modulating light-matter interactions at the nanoscale while maintaining minimal optical losses. In this study, we introduce a hybrid nanoantenna platform composed of Si/Si₃N₄/Au layers, which facilitates the tuning of resonant multipolar modes and their application in enhancing the photoluminescence (PL) of WSe₂ monolayer. By systematically varying the thickness of the Si₃N₄ spacer, we achieve modulation of both the spectral positions and spatial field distributions of the resonances associated with Si nanospheres, thereby enabling precise control over near-field confinement and far-field scattering characteristics. Optimal performance is observed with an 80 nm spacer thickness, where a distinct magnetic dipole resonance emerges near 750 nm. Additionally, fine-tuning the nanoparticle radius allows for controlled red- and blue-shifting of the resonant modes. These deliberately engineered resonances lead to a substantial enhancement of the PL emission from WSe₂ integrated onto the hybrid structure, with an enhancement factor approximating 1609. The observed enhancement is attributed to a combination of intensified local electromagnetic fields and strain-induced exciton funneling, presenting a promising methodology for the active manipulation of light emission within integrated nanophotonic devices.