Enhanced Conductivity Along Lateral Homojunction Interfaces of Atomically Thin Semiconductors

TL;DR

This study demonstrates that band engineering at monolayer/multilayer MoS2 interfaces enhances electrical conductivity and mobility, revealing new electronic properties due to interface charge states and band realignment.

Contribution

It provides experimental evidence that lateral homojunctions in MoS2 improve conductivity and mobility through interface charge states and band realignment, a novel insight into 2D material heterostructures.

Findings

Enhanced photoresponse at the interface due to band bending

Higher effective conductivity at the monolayer-multilayer interface

Improved field-effect mobility in heterojunction devices

Abstract

Energy band realignment at the interfaces between materials in heterostructures can give rise to unique electronic characteristics and non-trivial low-dimensional charge states. In a homojunction of monolayer and multilayer MoS$_2$, the thickness-dependent band structure implies the possibility of band realignment and a new interface charge state with properties distinct from the isolated layers. In this report, we probe the interface charge state using scanning photocurrent microscopy and gate-dependent transport with source-drain bias applied along the interface. Enhanced photoresponse observed at the interface is attributed to band bending. The effective conductivity of a material with a monolayer-multilayer interface of MoS$_2$ is demonstrated to be higher than that of independent monolayers or multilayers of MoS$_2$. A classic heterostructure model is constructed to interpret the electrical properties at the interface. Our work reveals that the band engineering at the transition metal dichalcogenides monolayer/multilayer interfaces can enhance the longitudinal conductance and field-effect mobility of the composite monolayer and multilayer devices.