  Graphene films prepared by heating the SiC(000-1) surface (the C-face of the
{0001} surfaces) in a Si-rich environment are studied using low-energy electron
diffraction (LEED) and low-energy electron microscopy (LEEM). Upon
graphitization, an interface with rt(43) x rt(43)-R7.6 degree symmetry is
observed by in situ LEED. After oxidation, the interface displays rt(3) x
rt(3)-R30 degree symmetry. Electron reflectivity measurements indicate that
these interface structures arise from a graphene-like "buffer layer" that forms
between the graphene and the SiC, similar to that observed on Si-face SiC. From
a dynamical LEED structure calculation for the oxidized C-face surface, it is
found to consist of a graphene layer sitting on top of a silicate (Si2O3)
layer, with the silicate layer having the well-known structure as previously
studied on bare SiC(000-1) surfaces. Based on this result, the structure of the
interface prior to oxidation is discussed.
