High-precision AFM cutting of graphene via improved electrode-free local anodic oxidation for electronic band engineering

Abstract

Atomic force microscopy (AFM) cutting of graphene via electrode-free localized anodic oxidation (EFLAO), with great convenience and flexible pattern design, has been widely used in various experimental investigations of graphene and its nanostructures. However, the fabrication precision, i.e., the width of an etched nanotrench, has been limited to 60-100 nm, hindering its potential for creating quantum confinement effects or engineering band structures. Here, we report a greatly improved EFLAO technique that achieves etching precision of nanotrenches as narrow as 15 nm, allowing for the reliable fabrication of graphene nanoribbon (GNR) arrays with a 50 nm period. We also demonstrated that these GNR arrays with such a small period can serve as a periodic gating electrode to engineer graphene band structures and produce artificial graphene superlattices. The improved EFLAO provides a convenient approach for fabricating high-precision graphene nanostructures using just an AFM setup, facilitating the exploration of quantum confinement effects and other quantum phenomena in graphene and other carbon materials.