Hybrid coupling enhances photoluminescence of monolayer MoS on plasmonic nanostructures.

The efficiency of photoluminescence (PL) of transition-metal dichalcogenides (TMDCs) significantly influences their practical applications in optoelectronic devices. In this work, we study multiple coupling among excitons, surface plasmons, and optical modes, and their effects on PL of monolayer MoS atop plasmonic nanohole arrays. Under the illumination of visible light, strong intensity enhancement of PL from monolayer MoS is observed in the system. We further demonstrate that there exist excitons induced from MoS, localized and propagating surface plasmons excited from nanoholes, and optical modes related to the incident laser. And hybrid coupling of those modes significantly improves the PL signals and also lightens the PL images of monolayer MoS. This work provides a unique way to improve the emission of monolayer TMDCs. The atomically thin TMDCs coupled to plasmonic metamaterials are also promising for advanced applications such as ultrathin integrated light-emission diodes, photodetection, and nanolasers.