  Graphene films prepared by heating the SiC(000-1) surface (the C-face of the
{0001} surfaces) in vacuum or in a Si-rich environment are compared. It is
found that different interface structures occur for the two situations. The
former yields a well known 3x3 reconstructed interface, whereas the latter
produces an interface with rt(43)xrt(43)-R\pm7.6 degrees symmetry. This
structure is shown to contain a graphene-like layer with properties similar to
the 6rt(3)x6rt(3)-R30 degrees "buffer layer" that forms on the Si(0001) surface
(the Si-face).
