# Electrical suppression of all nonradiative recombination pathways in monolayer semiconductors

## TL;DR

This paper demonstrates that electrostatic doping can nearly eliminate nonradiative recombination in monolayer TMDCs like MoS2 and WS2, achieving near-unity photoluminescence quantum yield without chemical passivation, thus easing defect density constraints.

## Contribution

It reveals that intrinsic electrostatic doping can suppress nonradiative pathways in TMDC monolayers, enabling high PL efficiency without defect passivation.

## Key findings

- PL QY reaches near-unity with electrostatic doping
- Neutral exciton recombination is fully radiative despite defects
- Eases defect density requirements for optoelectronic applications

## Abstract

Defects in conventional semiconductors substantially lower the photoluminescence (PL) quantum yield (QY), a key metric of optoelectronic performance that directly dictates the maximum device efficiency. Two-dimensional (2D) transition metal dichalcogenides (TMDCs), such as monolayer MoS2, often exhibit low PL QY for as-processed samples, which has typically been attributed to a large native defect density. We show that the PL QY of as-processed MoS2 and WS2 monolayers reaches near-unity when they are made intrinsic by electrostatic doping, without any chemical passivation. Surprisingly, neutral exciton recombination is entirely radiative even in the presence of a high native defect density. This finding enables TMDC monolayers for optoelectronic device applications as the stringent requirement of low defect density is eased.

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Source: https://tomesphere.com/paper/1905.03365