Visualisation of edge effects in side-gated graphene nanodevices

TL;DR

This study investigates edge effects in side-gated graphene nanodevices, revealing localized hole conduction at edges and the ability to tune electronic properties with side-gate voltages, while the bulk remains electron-doped.

Contribution

It provides detailed insights into edge conduction phenomena and demonstrates precise control of edge electronic properties using side-gates in graphene nanodevices.

Findings

Edges exhibit hole conduction within 60-125 nm width

Side-gates can switch edge conduction from hole to electron

Bulk graphene remains electron-doped and unaffected by side-gates

Abstract

Using local scanning electrical techniques we study edge effects in side-gated Hall nanodevices made of epitaxial graphene. We demonstrate that lithographically defined edges of the graphene channel exhibit hole conduction within the narrow band of ~60-125 nm width, whereas the bulk of the material is electron doped. The effect is the most pronounced when the influence of atmospheric contamination is minimal. We also show that the electronic properties at the edges can be precisely tuned from hole to electron conduction by using moderate strength electrical fields created by side-gates. However, the central part of the channel remains relatively unaffected by the side-gates and retains the bulk properties of graphene.