Competing mechanisms of local photoluminescence quenching and enhancement in the quantum tunneling regime at 2D TMDC/hBN/plasmonic interfaces

Abstract

Owing to the extraordinary physical and chemical properties, and the potential to couple with nanoplasmonic structures, two-dimensional (2D) transition metal dichalcogenides are promising materials for next-generation (opto-)electronic devices. Targeting the application stage, it is essential to understand the mechanisms of photoluminescence (PL) quenching and enhancement at the nanoscale. In this work, using monolayer MoSe2/hBN heterostructure on Au nanotriangles (NTs) as an example, we report on the local PL quenching and enhancement in the quantum tunneling regime at MoSe2/hBN/plasmonic nanostructure interfaces. By exploiting tip-enhanced photoluminescence spectroscopy, we were able to resolve and image the nanostructures locally. Moreover, by studying the different near-field emission behavior of MoSe2/SiO2, MoSe2/hBN, MoSe2/NT, and MoSe2/hBN/NT, we investigate the localized surface plasmon resonance, electron tunneling, and highly localized strain as the three competing mechanisms of local PL quenching and enhancement in the quantum tunneling regime at the nanoscale.