Monolayer MoS2 Bandgap Modulation by Dielectric Environments and Tunable Bandgap Transistors

TLDR

Semiconductors with moderate bandgaps have enabled modern electronics, and the scaling to nanometer dimensions has introduced two‑dimensional semiconductors whose bandgaps were traditionally considered intrinsic and environment‑independent. The study aims to show that a monolayer 2D semiconductor’s bandgap strongly depends on its dielectric environment and to propose a tunable bandgap transistor based on this property. The authors propose a tunable bandgap transistor built from a monolayer 2D semiconductor whose bandgap can be modulated by surrounding dielectrics. They find that the monolayer MoS₂ bandgap decreases from 2.8 eV to 1.9 eV when the dielectric environment is altered.

Abstract

Abstract Semiconductors with a moderate bandgap have enabled modern electronic device technology, and the current scaling trends down to nanometer scale have introduced two-dimensional (2D) semiconductors. The bandgap of a semiconductor has been an intrinsic property independent of the environments and determined fundamental semiconductor device characteristics. In contrast to bulk semiconductors, we demonstrate that an atomically thin two-dimensional semiconductor has a bandgap with strong dependence on dielectric environments. Specifically, monolayer MoS 2 bandgap is shown to change from 2.8 eV to 1.9 eV by dielectric environment. Utilizing the bandgap modulation property, a tunable bandgap transistor, which can be in general made of a two-dimensional semiconductor, is proposed.