Surface plasmon polariton-enhanced photoluminescence of monolayer MoS2 on suspended periodic metallic structures

Plasmonic nanostructures have garnered tremendous interest in enhanced light-matter interaction because of their unique capability of extreme field confinement in nanoscale, especially beneficial for boosting the photoluminescence (PL) signals of weak light-matter interaction materials such as transition metal dichalcogenides atomic crystals. Here we report the surface plasmon polariton (SPP)-assisted PL enhancement of MoS2 monolayer via a suspended periodic metallic (SPM) structure. Without involving metallic nanoparticle-based plasmonic geometries, the SPM structure can enable more than two orders of magnitude PL enhancement. Systematic analysis unravels the underlying physics of the pronounced enhancement to two primary plasmonic effects: concentrated local field of SPP enabled excitation rate increment (45.2) as well as the quantum yield amplification (5.4 times) by the SPM nanostructure, overwhelming most of the nanoparticle-based geometries reported thus far. Our results provide a powerful way to boost two-dimensional exciton emission by plasmonic effects which may shed light on the on-chip photonic integration of 2D materials.