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Lookup NU author(s): Professor Patrick Briddon, Dr Mark Rayson
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
The formation of extended defects in graphene from the coalescence of individual mobile vacancies can significantly alter its mechanical, electrical and chemical properties. We present the results of ab initio simulations which demonstrate that the strain created by multi-vacancy complexes in graphene determine their overall growth morphology when formed from the coalescence of individual mobile lattice vacancies. Using density functional theory, we map out the potential energy surface for the motion of mono-vacancies in the vicinity of multi-vacancy defects. The inhomogeneous bond strain created by the multi-vacancy complexes strongly biases the activation energy barriers for single vacancy motion over a wide area. Kinetic Monte Carlo simulations based on rates from ab initio derived activation energies are performed to investigate the dynamical evolution of single vacancies in these strain fields. The resultant coalescence processes reveal that the dominant morphology of multi-vacancy complexes will consist of vacancy lines running in the two primary crystallographic directions, and that more thermodynamically stable structures, such as holes, are kinetically inaccessible from mono-vacancy aggregation alone.
Author(s): Trevethan T, Latham CD, Heggie MI, Briddon PR, Rayson MJ
Publication type: Article
Publication status: Published
Journal: Nanoscale
Year: 2014
Volume: 6
Issue: 5
Pages: 2978-2986
Print publication date: 07/03/2014
Online publication date: 21/01/2014
Acceptance date: 15/01/2014
Date deposited: 07/08/2015
ISSN (print): 2040-3364
ISSN (electronic): 2040-3372
Publisher: RSC Publications
URL: http://dx.doi.org/10.1039/c3nr06222h
DOI: 10.1039/c3nr06222h
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