Conversion of Classical Light Emission from a Nanoparticle-Strained WSe2 Monolayer into Quantum Light Emission via Electron Beam Irradiation

Solid-state single photon emitters (SPEs) within atomically thin transition metal dichalcogenides (TMDs) have recently attracted interest as scalable quantum light sources for quantum photonic technologies. Among TMDs, WSe2 monolayers (MLs) are promising for the deterministic fabrication and engineering of SPEs using local strain fields. The ability to reliably produce isolatable SPEs in WSe2 is currently impeded by the presence of numerous spectrally overlapping states that occur at strained locations. Here nanoparticle (NP) arrays with precisely defined positions and sizes are employed to deterministically create strain fields in WSe2 MLs, thus enabling the systematic investigation and control of SPE formation. Using this platform, electron beam irradiation at NP-strained locations transforms spectrally overlapped sub-bandgap emission states into isolatable, anti-bunched quantum emitters. The dependence of the emission spectra of WSe2 MLs as a function of strain magnitude and exposure time to electron beam irradiation is quantified and provides insight into the mechanism for SPE production. Excitons selectively funnel through strongly coupled sub-bandgap states introduced by electron beam irradiation, which suppresses spectrally overlapping emission pathways and leads to measurable anti-bunched behavior. The findings provide a strategy to generate isolatable SPEs in 2D materials with a well-defined energy range.

Automated summary

Solid-state single photon emitters (SPEs) in atomically thin transition metal dichalcogenides (TMDs) have gained attention as scalable quantum light sources. In this study, strain fields were created in WSe2 monolayers (MLs) using nanoparticle (NP) arrays, leading to the formation of isolatable SPEs. The emission spectra of WSe2 MLs were quantified to provide insight into the mechanism for SPE production. Excitons selectively funneled through strongly coupled sub-bandgap states, resulting in anti-bunched behavior.