Weak localization and Raman study of anisotropically etched graphene antidots

TL;DR

This study investigates a selective crystallographic etching process in graphene that enhances zigzag edges, using weak localization and Raman spectroscopy to confirm the edge structure improvements over traditional methods.

Contribution

It introduces a novel etching method that selectively creates zigzag edges in graphene nanostructures, verified by weak localization and Raman measurements.

Findings

Enhanced zigzag edge formation compared to reactive ion etching.

Weak localization and Raman data confirm increased intervalley scattering.

Selective etching preserves atomic-scale edge structure.

Abstract

We study a crystallographic etching process of graphene nanostructures where zigzag edges can be prepared selectively. The process involves heating exfoliated single-layer graphene samples with a predefined pattern of antidot arrays in an argon atmosphere at 820 C, which selectively removes carbon atoms located on armchair sites. Atomic force microscopy and scanning electron microscopy cannot resolve the structure on the atomic scale. However, weak localization and Raman measurements - which both probe intervalley scattering at armchair edges - indicate that zigzag regions are enhanced compared to samples prepared with oxygen based reactive ion etching only.