Tailored emission spectrum of 2D semiconductors using plasmonic nanocavities

Tailoring light–matter interactions in monolayer MoS2 is critical for its use in optoelectronic and nanophotonic devices. While significant effort has been devoted to enhancing the photoluminescence intensity in monolayer MoS2, tailoring of the emission spectrum including complex excitonic states remains largely unexplored. Here, we demonstrate that the peak emission wavelengths of the A and B excitons can be tuned up to 40 and 25 nm, respectively, by integrating monolayer MoS2 into a plasmonic nanocavity with tunable plasmon resonances. Contrary to the intrinsic photoluminescence spectrum of monolayer MoS2, we are also able to create a dominant B exciton peak when the nanocavity is resonant with its emission. Additionally, we observe a 1200-fold enhancement of the A exciton emission and a 6100-fold enhancement of the B exciton emission when normalized to the area under a single nanocavity and compared to a control sample on thermal oxide.