Photogating of mono- and few-layer MoS2

TL;DR

This paper demonstrates a reversible, light-controlled photogating effect in mono- and few-layer MoS2, enabling precise charge carrier modulation without electrical contacts, influenced by environmental molecules and tunable by light intensity.

Contribution

It introduces a novel, contactless method to control charge density in MoS2 using photogating influenced by environmental molecules and light exposure.

Findings

Charge carrier density can be modulated by nearly two orders of magnitude.

Environmental molecules affect the charge transfer and can be removed by light.

Photogating efficiency is comparable to electrostatic gating.

Abstract

We describe a photogating effect in mono- and few-layer MoS2, which allows the control of the charge carrier density by almost two orders of magnitude without electrical contacts. Our Raman studies are consistent with physisorbed environmental molecules, that effectively deplete the intrinsically n-doped charge carrier system via charge transfer, and which can be gradually removed by the exposure to light. This photogating process is reversible and precisely tunable by the light intensity. The photogating efficiency is quantified by comparison with measurements on electrostatically gated MoS2.