Tailoring interfacial nanostructures at graphene/transition metal dichalcogenide heterostructures

TL;DR

This paper demonstrates precise patterning and size tuning of transition metal dichalcogenide nanostructures at graphene/TMD heterostructure interfaces, enabling custom-designed mixed-dimensional devices with controlled electrostatic properties.

Contribution

It introduces a method for nanometer-precision patterning of TMD nanostructures at heterostructure interfaces, including size control and phase transition observation.

Findings

TMD nanostructures can be created at specific interface sites.

Nanostructure sizes can be precisely tuned.

A phase transition from hexagonal to monoclinic phase is observed.

Abstract

Integration of two-dimensional (2D) van der Waals (vdWs) materials with non-2D materials to realize mixed-dimensional heterostructures has potential for creating functional devices beyond the reach of existing materials and has long been a pursuit of the material science community. Here we report the patterning of monolayer/bilayer transition metal dichalcogenide (TMD) nanostructures with nanometer-precision, tunable sizes and sites at interfaces of graphene/TMD heterostructures. Our experiments demonstrate that the TMD nanostructures can be created at selected positions of the interface using scanning tunneling microscope lithography and, more importantly, the sizes of the interfacial TMD nanostructures can be tuned with nanoscale precise by merging adjacent TMD nanostructures or by further tailoring. A structural phase transition from hexagonal phase in bulk TMD to monoclinic phase in the interfacial nanostructures is explicitly observed, which locally introduce well-defined electrostatic potentials on graphene. These results not only enable the creation of high-quality patterned p-n junctions in vdWs heterostructures, but also provide a new route to realize custom-designed mixed-dimensional heterostructures.