1202.0561 (Joseph M. Wofford et al.)

Extraordinary epitaxial alignment of graphene islands on Au (111):
toward single-crystal growth    [PDF]

Joseph M. Wofford, Elena Starodub, Andrew L. Walter, Shu Nie, Aaron Bostwick, Norman C. Bartelt, Konrad Thürmer, Eli Rotenberg, Kevin F. McCarty, Oscar D. Dubon

Pristine, single-crystalline graphene displays a unique collection of
remarkable electronic properties that arise from its two-dimensional, honeycomb
structure. Realizing the full potential of graphene necessitates its production
at the wafer scale in single-crystal form, a fundamental materials requirement
for advanced electronics. Despite considerable efforts, single crystalline
graphene films remain elusive. Using in-situ low-energy electron microscopy, we
show that evaporating carbon onto the Au (111) surface forms quasi-single
crystalline, epitaxial graphene. The monolayer film results from the
coalescence of dendritic graphene islands that nucleate at high density. Over
95% of the islands can be identically aligned with respect to the Au substrate.
Remarkably, the dominant island orientation-which aligns the graphene and gold
lattices-is not the better lattice-matched 30\circ rotated orientation.
Scanning tunneling microscopy and angle-resolved photoemission spectroscopy
show that the epitaxial film is only weakly coupled to the Au surface, which
remains reconstructed under the slightly doped p-type graphene. The linear
electronic dispersion characteristic of free-standing graphene is retained.
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.

View original: http://arxiv.org/abs/1202.0561