# Overbias photon emission from light-emitting devices based on monolayer transition metal dichalcogenides

## TL;DR

This paper investigates overbias photon emission in TMD-based tunneling LEDs, revealing a non-thermal exciton generation mechanism via two-electron coherent tunneling, advancing understanding of their physical processes.

## Contribution

It uncovers the mechanism behind overbias emission in TMD LEDs, demonstrating a two-electron coherent tunneling process responsible for photon energies exceeding the applied potential.

## Key findings

- Overbias emission occurs near half the optical bandgap energy.
- Emission is non-thermal and linked to exciton generation.
- Two-electron coherent tunneling explains the overbias photons.

## Abstract

Tunneling light-emitting devices (LEDs) based on transition metal dichalcogenides (TMDs) and other 2D materials are a new platform for on-chip optoelectronic integration. Some of the physical processes underlying this LED architecture are not fully understood, especially the emission at photon energies higher than the applied electrostatic potential, so-called overbias emission. Here we report overbias emission for potentials that are near half of the optical bandgap energy in TMD-based tunneling LEDs. We show that this emission is not thermal in nature, but consistent with exciton generation via a two-electron coherent tunneling process.