Graphene Nucleation on a Surface-Molten Copper Catalyst: Quantum Chemical Molecular Dynamics Simulations

Hai-Bei Li , Alister Page , Christian Hettich , Balint Aradi , Christoph Köhler , Thomas Frauenheim , Stephan Irle and Keiji Morokuma
Chem. Sci.,2014, Accepted Manuscript
DOI: 10.1039/C4SC00491D
Received 14th February 2014 , Accepted 16th May 2014
First published on the web 16th May 2014

Chemical vapor deposition (CVD) graphene growth on Cu(111) has been modeled with quantum chemical molecular dynamics (QM/MD) simulations. These simulations demonstrate at the atomic level how graphene forms on Cu surfaces. In contrast to other popular catalysts, such as nickel and iron, copper is in a surface molten state throughout graphene growth at CVD-relevant temperatures, and graphene growth takes place without subsurface diffusion of carbon. Surface Cu atoms have remarkably high mobility on the Cu(111) surface, both before and after graphene nucleation. This surface mobility drives “defect healing” processes in the nucleating graphene structure that convert defects such as pentagons and heptagons into carbon hexagons. Consequently, the graphene defects that become “kinetically trapped” using other catalysts, such as Ni and Fe, are less commonly observed in the case of Cu. We propose this mechanism to be the basis of copper’s ability to form high-quality, large-domain graphene flakes.Chemical vapor deposition (CVD) graphene growth on Cu(111) has been modeled with quantum chemical molecular dynamics (QM/MD) simulations. These simulations demonstrate at the atomic level how graphene forms on Cu surfaces. In contrast to other popular catalysts, such as nickel and iron, copper is in a surface molten state throughout graphene growth at CVD-relevant temperatures, and graphene growth takes place without subsurface diffusion of carbon. Surface Cu atoms have remarkably high mobility on the Cu(111) surface, both before and after graphene nucleation. This surface mobility drives “defect healing” processes in the nucleating graphene structure that convert defects such as pentagons and heptagons into carbon hexagons. Consequently, the graphene defects that become “kinetically trapped” using other catalysts, such as Ni and Fe, are less commonly observed in the case of Cu. We propose this mechanism to be the basis of copper’s ability to form high-quality, large-domain graphene flakes.

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