  The growth of graphene by catalytic decomposition of ethylene on Cu(111) in
an ultra-high vacuum system was investigated with low energy electron
diffraction, low energy electron microscopy, and atomic force microscopy.
Attempts to form a graphene overlayer using ethylene at pressures as high as 10
mTorr and substrate temperatures as high as 900 $^\circ$C resulted in almost no
graphene growth. By using an argon overpressure, the growth of epitaxial
graphene on Cu(111) was achieved. The suppression of graphene growth without
the use of an argon overpressure is attributed to Cu sublimation at elevated
temperatures. During the initial stages of growth, a random distribution of
rounded graphene islands is observed. The predominant rotational orientation of
the islands is within $\pm1^\circ$ of the Cu(111) substrate lattice.
