Experimentally Engineering the Edge Termination of Graphene Nanoribbons

TL;DR

This study demonstrates precise engineering of graphene nanoribbon edges using hydrogen plasma etching, revealing atomic structures and chemical terminations that influence electronic and magnetic properties.

Contribution

It provides detailed atomic-level insights into plasma-etched GNR edges and their chemical nature, advancing control over GNR properties.

Findings

Edges are hydrogen-terminated with no rehybridization.

Edges are flat and free of structural reconstructions.

Edge states are present in zigzag and chiral edges.

Abstract

The edges of graphene nanoribbons (GNRs) have attracted much interest due to their potentially strong influence on GNR electronic and magnetic properties. Here we report the ability to engineer the microscopic edge termination of high quality GNRs via hydrogen plasma etching. Using a combination of high-resolution scanning tunneling microscopy and first-principles calculations, we have determined the exact atomic structure of plasma-etched GNR edges and established the chemical nature of terminating functional groups for zigzag, armchair and chiral edge orientations. We find that the edges of hydrogen-plasma-etched GNRs are generally flat, free of structural reconstructions and are terminated by hydrogen atoms with no rehybridization of the outermost carbon edge atoms. Both zigzag and chiral edges show the presence of edge states.