  We have used low-energy electron microscopy and diffraction to examine the
significance of lattice orientation in graphene growth on Cu(001). Individual
graphene domains undergo anisotropic growth on the Cu surface, and develop into
lens shapes with their long axes roughly aligned with the Cu<100> in-plane
directions. The long axis of a lens-shaped domain is only rarely oriented along
a C<11> direction, suggesting that carbon attachment at "zigzag" graphene
island edges is unfavorable. A kink-mediated adatom attachment process is
consistent with the behavior observed here and reported in the literature. The
details of the ridged moire pattern formed by the superposition of the graphene
lattice on the (001) Cu surface also evolve with the graphene lattice
orientation, and are predicted well by a simple geometric model. Managing the
kink-mediated growth mode of graphene on Cu(001) will be necessary for the
continued improvement of this graphene synthesis technique.
