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.