Atom-Scale Reaction Pathways and Free-Energy Landscapes in Oxygen Plasma Etching of Graphene.
We report first-principles molecular dynamics calculations combined with rare events sampling techniques that clarify atom-scale mechanisms of oxygen plasma etching of graphene. The obtained reaction pathways and associated free-energy landscapes show that the etching proceeds near vacancies via a two-step mechanism, formation of precursor lactone structures and the subsequent exclusive CO2 desorption. We find that atomic oxygen among the plasma components is most efficient for etching, providing a guidline in tuning the plasma conditions.
†Department of Applied Physics, The University of Tokyo, Hongo, Tokyo 113-8656, Japan.
Kenichi
K
Koizumi
‡IPCMS, CNRS, and University of Strasbourg, UMR 7504, F-67034 Strasbourg cedex 2, France.
Mauro
M
Boero
¶Department of Materials Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.
Yasuteru
Y
Shigeta
†Department of Applied Physics, The University of Tokyo, Hongo, Tokyo 113-8656, Japan.
Atsushi
A
Oshiyama
etching; first-principles simulations; free energy; graphene; oxygen; reactive dynamics