Electrically pumped single-defect light emitters in WSe$_2$

TL;DR

This paper reports the fabrication of electrically pumped single-defect light emitters in monolayer WSe$_2$ using van der Waals heterostructures, demonstrating sharp defect luminescence, electric field tuning, and potential for integration in nano-photonics.

Contribution

It introduces a new method to create electrically pumped quantum emitters in atomically thin semiconductors with tunable emission energy.

Findings

Sharp luminescence spectra from individual defects under electrical excitation

Emission energy tuning by more than 1 meV with electric field

Potential for integration with existing nano-photonics technologies

Abstract

Recent developments in fabrication of van der Waals heterostructures enable new type of devices assembled by stacking atomically thin layers of two-dimensional materials. Using this approach, we fabricate light-emitting devices based on a monolayer WSe$_2$, and also comprising boron nitride tunnelling barriers and graphene electrodes, and observe sharp luminescence spectra from individual defects in WSe$_2$ under both optical and electrical excitation. This paves the way towards the realization of electrically-pumped quantum emitters in atomically thin semiconductors. In addition we demonstrate tuning by more than 1 meV of the emission energy of the defect luminescence by applying a vertical electric field. This provides an estimate of the permanent electric dipole created by the corresponding electron-hole pair. The light-emitting devices investigated in our work can be assembled on a variety of substrates enabling a route to integration of electrically pumped single quantum emitters with existing technologies in nano-photonics and optoelectronics.