Discrete quantum dot like emitters in monolayer MoSe2: Spatial mapping, Magneto-optics and Charge tuning

TL;DR

This paper reports the discovery and characterization of quantum dot-like emitters in monolayer MoSe2, demonstrating their spatial localization, tunability via magnetic and electric fields, and potential for optoelectronic applications.

Contribution

It introduces spectrally sharp, localized emission in MoSe2 monolayers and explores their magnetic and charge tuning properties, advancing understanding of quantum emitters in 2D materials.

Findings

Localized emission correlated with wrinkles in MoSe2

Emitters exhibit an exciton g-factor near -4

Discrete charge jumps observed with voltage changes

Abstract

Transition metal dichalcogenide monolayers such as MoSe2,MoS2 and WSe2 are direct bandgap semiconductors with original optoelectronic and spin-valley properties. Here we report spectrally sharp, spatially localized emission in monolayer MoSe2. We find this quantum dot like emission in samples exfoliated onto gold substrates and also suspended flakes. Spatial mapping shows a correlation between the location of emitters and the existence of wrinkles (strained regions) in the flake. We tune the emission properties in magnetic and electric fields applied perpendicular to the monolayer plane. We extract an exciton g-factor of the discrete emitters close to -4, as for 2D excitons in this material. In a charge tunable sample we record discrete jumps on the meV scale as charges are added to the emitter when changing the applied voltage. The control of the emission properties of these quantum dot like emitters paves the way for further engineering of the light matter interaction in these atomically thin materials.