Quantum plasmonics with 2D lateral heterostructures

Two-dimensional (2D) transition metal dichalcogenides (TMDs) are promising 2D materials with interesting optoelectronic, catalytic and sensing applications whose nanoscale optical characterization provides detailed structure-function information which is a challenge for typical far-field diffraction-limited techniques. We investigate monolayer and few-layer 2D materials and heterostructures using tip-enhanced Raman scattering (TERS) and tip-enhanced photoluminescence (TEPL) with a few nanometer spatial resolution. We investigate the limits of signal enhancement by varying the tip-sample gap and reveal quantum plasmonic quenching for sub-nanometer gaps. Quantum plasmonics provides a new regime for the generation of excitons and trions in 2D materials. We present examples of near field control of optical signals from excitons and trions, and investigate various enhancement mechanisms.