Computational study of graphene growth on copper b

Authors: Simone Taioli

Publish Date: 2014/06/18

Volume: 20, Issue: 7, Pages: 2260-

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Abstract

In this work the growth of a graphene monolayer on copper substrate as typically achieved via chemical vapor deposition of propene C3H6 was investigated by firstprinciples and kinetic Monte Carlo calculations A comparison between calculated C1s corelevel binding energies and electron spectroscopy measurements showed that graphene nucleates from isolated carbon atoms adsorbed on surface defects or subsuperficial layers upon hydrocarbon fragmentation In this respect ab initio nudged elastic band simulations yield the energetic barriers characterizing the diffusion of elemental carbon on the Cu111 surface and atomic carbon uptake by the growing graphene film Our calculations highlight a strong interaction between the growing film edges and the copper substrate indicative of the importance of the grain boundaries in the epitaxy process Furthermore we used activation energies to compute the reaction rates for the different mechanisms occurring at the carbon–copper interface via harmonic transition state theory Finally we simulated the longtime system growth evolution through a kinetic Monte Carlo approach for different temperatures and coverage Our ab initio and Monte Carlo simulations of the outofequilibrium system point towards a growth model strikingly different from that of standard film growth Graphene growth on copper turns out to be a catalytic thermallyactivated process that nucleates from carbon monomers proceeds by adsorption of carbon atoms and is not selflimiting Furthermore graphene growth seems to be more effective at carbon supersaturation of the surface—a clear fingerprint of a large activation barrier for C attachment Our growth model and computational results are in good agreement with recent Xray photoelectron spectroscopy experimental measurementsST acknowledges financial support from both the European Science Foundation under the INTELBIOMAT Exchange Grant “Interdisciplinary Approaches to Functional Electronic and Biological Materials” and the Bruno Kessler Foundation FBK under the Graphene Flagship research initiative Work Package 9 Energy and Work Package 10 Nanocomposites This work was partially accomplished under the “Research Mobility Scheme” provided by FBK Furthermore ST gratefully acknowledges the Institute of Advanced Studies in Bologna for the support given under his ISA research fellowship and the “Istituto Nazionale di Fisica Nucleare INFN” through the supercomputing agreement granted to the Bruno Kessler Foundation Finally this work made use of the large scale computational facilities KORE Bruno Kessler Foundation Trento and HECToR the UK’s national highperformance computing service

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