Spectrally resolved far-field emission pattern of single photon emitters in MoS2

TL;DR

This study investigates the optical properties and emission patterns of single photon emitters in monolayer MoS2, revealing sub-bandgap luminescence lines and their relation to defect states through experimental and theoretical analysis.

Contribution

It provides the first experimental resolution of sub-bandgap emission lines in MoS2 and links them to sulfur vacancies predicted by ab initio theory.

Findings

Resolved sub-bandgap luminescence lines in MoS2

Demonstrated dependence of emission on photon energy and momentum

Confirmed strong interaction of defect states within the Brillouin zone

Abstract

We explore the optical dipole orientation of single photon emitters in monolayer MoS2 as produced by a focused helium ion beam. The single photon emitters can be understood as single sulfur vacancies. The corresponding far-field luminescence spectra reveal several photoluminescence lines below the dominating luminescence of the exciton in MoS2. These sub-bandgap emission lines were predicted by ab initio theory, but they have never been resolved in luminescence experiments because of their small amplitude. We reveal the lines by their dependence as a function of the photon energy and momentum as measured in the back focal plane of the optical circuitry. The agreement between theory and experiment suggests that the defect states interact strongly within the Brillouin zone.