Pristine, single-crystalline graphene displays a unique collection of remarkable electronic properties that arise from its two-dimensional, honeycomb structure. Using in-situ low-energy electron microscopy, we show that when deposited on the (111) surface of Au carbon forms such a structure. The resulting monolayer, epitaxial film is formed by the coalescence of dendritic graphene islands that nucleate at a high density. Over 95% of these islands can be identically aligned with respect to each other and to the Au substrate. Remarkably, the dominant island orientation is not the better lattice-matched 30^{\circ} rotated orientation but instead one in which the graphene [01] and Au [011] in-plane directions are parallel. The epitaxial graphene film is only weakly coupled to the Au surface, which maintains its reconstruction under the slightly p-type doped graphene. The linear electronic dispersion characteristic of free-standing graphene is retained regardless of orientation. That a weakly interacting, non-lattice matched substrate is able to lock graphene into a particular orientation is surprising. This ability, however, makes Au(111) a promising substrate for the growth of single crystalline graphene films.
@article{arxiv.1202.0561,
title = {Extraordinary epitaxial alignment of graphene islands on Au(111)},
author = {Joseph M. Wofford and Elena Starodub and Andrew L. Walter and Shu Nie and Aaron Bostwick and Norman C. Bartelt and Konrad Thürmer and Eli Rotenberg and Kevin F. McCarty and Oscar D. Dubon},
journal= {arXiv preprint arXiv:1202.0561},
year = {2012}
}