Intrinsic disorder in graphene on transition metal dichalcogenide heterostructures

TL;DR

This paper investigates how intrinsic defects in transition metal dichalcogenides (TMDs) as substrates affect the electronic quality of graphene heterostructures, revealing defect-induced scattering that degrades device performance.

Contribution

It provides direct experimental evidence that intrinsic TMD defects cause scattering in graphene, highlighting a key factor affecting heterostructure quality.

Findings

Intrinsic defects in TMDs induce scattering in graphene.

Graphene on TMDs shows degraded electronic properties compared to hBN.

Defect-induced scattering significantly impacts heterostructure performance.

Abstract

The electronic properties of two-dimensional materials such as graphene are extremely sensitive to their environment, especially the underlying substrate. Planar van der Waals bonded substrates such as hexagonal boron nitride (hBN) have been shown to greatly improve the electrical performance of graphene devices by reducing topographic variations and charge fluctuations compared to amorphous insulating substrates}. Semiconducting transition metal dichalchogenides (TMDs) are another family of van der Waals bonded materials that have recently received interest as alternative substrates to hBN for graphene as well as for components in novel graphene-based device heterostructures. Additionally, their semiconducting nature permits dynamic gate voltage control over the interaction strength with graphene. Through local scanning probe measurements we find that crystalline defects intrinsic to TMDs induce scattering in graphene which results in significant degradation of the heterostructure quality, particularly compared to similar graphene on hBN devices.