Manipulating single photon emitter radiative lifetime in transition-metal dichalcogenides through Forster resonance energy transfer to graphene

Abstract: Structural defects can crucially impact the optical response of monolayer (ML) thick materials as they enable trapping sites for excitons. These trapped excitons appear in photoluminescence spectra as new emissions below the free bright exciton and it can be exploited for single photon emissions (SPE). In this work we outline criteria, within our frame work, by which single photon emission can be detected in two dimensional materials and we explore how these criteria can be fulfilled in atomically thin transition metal dichalcogenides (TMD). In particular, we model the effect of defects, in accordance with the most common experimental realisations, on the spatial autocorrelation function of the random disorder potential. Moreover, we provide a way to control the radiative lifetime of these emissions by a hybride heterostructrue of the ML TMD with a graphene sheet and a dielectric spacer that enables the Forster resonance energy transfer process. Our work predict that the corresponding SPE quenched radiative lifetime will be in the picosecond range, this time scale is in good agreement with the recently measured exciton lifetime in this heterostructures