The Removal of Single Layers from Multi-Layer Graphene by Low Energy Electron Stimulation

TL;DR

This paper demonstrates that low energy electron stimulation can selectively remove single atomic layers from multi-layer graphene, offering a controlled etching method distinct from reactive plasma techniques.

Contribution

It introduces a novel electron-stimulation technique for layer removal in multi-layer graphene, differing from traditional reactive plasma methods.

Findings

Layer removal rate depends on exposure time, bias, and pre-annealing.

Electron stimulation causes layer-by-layer removal without large pits.

Removal mechanism involves electron-stimulated dissociation of carbon atoms.

Abstract

The removal of single atomic layers from multi-layer graphene using a He plasma is reported. By applying sample biases of -60 and +60 V during He plasma exposure, layer removal is found to be due to electrons instead of He ions or neutrals in the plasma. The rate of layer removal depends on exposure time, sample bias and pre-annealing treatments. Optical contrast microscopy and atomic force microscopy studies show that the removal of C atoms occurs approximately one layer at a time across the entire multi-layer sample with no observable production of large pits or reduction in lateral dimensions. Layer removal is proposed to arise from the electron-stimulated dissociation of C atoms from the basal plane. This process differs from plasma techniques that use reactive species to etch multi-layer graphene.