The formation mechanism of multiple vacancies and amorphous graphene under electron irradiationElectronic supplementary information (ESI) available: Efs of certain haeckelites observed in the NEMD simulation of Vns, for n = 4, 6, and 8; the area of pentagon and heptagon of the 5|7 pair of certain haeckelites, and the resulted area compensation by 5|7 pair relative to two hexagons in the perfect graphene; probability distributions of bond lengths in the representative configurations of Vns for n

• Main Authors: Zhao, Ruiqi, Zhuang, Jianing, Liang, Zilin, Yan, Tianying, Ding, Feng
• Format: Journal Article
• Language: English
• Published: 30.04.2015
• ISSN: 2040-3364; 2040-3372
• DOI: 10.1039/c5nr00552c

The evolution of multiple vacancies (V n s) in graphene under electron irradiation (EI) was explored systematically by long time non-equilibrium molecular dynamics simulations, with n varying from 4 to 40. The simulations showed that the V n s form haeckelites in the case with small n , while forming holes as n increases. The scale of the haeckelites, characterized by the number of pentagon-heptagon pairs, grows linearly with n . Such a linear relationship can be interpreted as a consequence of compensating the missing area, caused by the V n s, in order to maintain the area of the perfect sp 2 network by self-healing. Beyond that, the scale of the haeckelite vs. the density of missing atoms is predicted to be S h ∼ 6 D n , where S h and D n are the percentage of non-hexagonal rings and missing atoms, respectively. This study provides an intuitive picture of the formation of amorphous graphene under EI and the quantitative understanding of the mechanism. The formation of amorphous graphene is theoretically found to be highly correlated to the concentration of atoms lost.