A computational analysis of graphene adhesion on amorphous silica
E Paek and GS Hwang, JOURNAL OF APPLIED PHYSICS, 113, 164901 (2013).
We present a computational analysis of the morphology and adhesion energy of graphene on the surface of amorphous silica (a-SiO2). The a-SiO2 model surfaces obtained from the continuous random network model- based Metropolis Monte Carlo approach show Gaussian-like height distributions with an average standard deviation of 2.91 +/- 0.56 angstrom, in good agreement with existing experimental measurements (1.68-3.7 angstrom). Our calculations clearly demonstrate that the optimal adhesion between graphene and a-SiO2 occurs when the graphene sheet is slightly less corrugated than the underlying a-SiO2 surface. From morphology analysis based on fast Fourier transform, we find that graphene may not conform well to the relatively small jagged features of the a-SiO2 surface with wave lengths of smaller than 2 nm, although it generally exhibits high-fidelity conformation to a-SiO2 topographic features. For 18 independent samples, on average the van der Waals interaction at the graphene/a-SiO2 interface is predicted to vary from E-vdW = 0.93 eV to 1.56 eV per unit cross-sectional area (nm(2)) of the a-SiO2 slab, depending on the choice of 12-6 Lennard-Jones potential parameters, while the predicted strain energy of corrugated graphene on a-SiO2 is E-st = 0.25-0.36 eV/nm(2). The calculation results yield the graphene/a-SiO2 adhesion energy of about E-ad =0.7-1.2 eV/nm, given E-ad = E-vdW-E-st. We also discuss how the adhesive strength is affected by the morphological conformity between the graphene sheet and the a-SiO2 surface. (C) 2013 AIP Publishing LLC.
Return to Publications page