Spontaneous edge-defect formation and defect-induced conductance suppression in graphene nanoribbons

TL;DR

This study uses first-principles calculations to investigate how edge defects form and affect electrical conductance in zigzag graphene nanoribbons, revealing spontaneous defect formation and conductance suppression.

Contribution

It provides new insights into the spontaneous formation of edge defects and their impact on conductance in ZGNRs through first-principles analysis.

Findings

Adatoms are highly mobile at room temperature.

Vacancies are nearly immobile along the edge.

Defect formation drastically suppresses conductance.

Abstract

We present a first-principles study of the migration and recombination of edge defects (carbon adatom and/or vacancy) and their influence on electrical conductance in zigzag graphene nanoribbons (ZGNRs). It is found that at room temperature, the adatom is quite mobile while the vacancy is almost immobile along the edge of ZGNRs. The recombination of an adatom-vacancy pair leads to a pentagon-heptagon ring defect structure having a lower energy than the perfect edge, implying that such an edge-defect can be formed spontaneously. This edge defect can suppresses the conductance of ZGNRs drastically, which provides some useful hints for understanding the observed semiconducting behavior of the fabricated narrow GNRs.