  Graphene-covered copper surfaces have been exposed to borazine, (BH)3(NH)3,
with the resulting surfaces characterized by low-energy electron microscopy.
Although the intent of the experiment was to form hexagonal boron nitride
(h-BN) on top of the graphene, such layers were not obtained. Rather, in
isolated surface areas, h-BN is found to form micrometer-size islands that
substitute for the graphene. Additionally, over nearly the entire surface, the
properties of the layer that was originally graphene is observed to change in a
manner that is consistent with the formation of a mixed h-BN/graphene alloy,
i.e. h-BNC alloy. Furthermore, following the deposition of the borazine, a
small fraction of the surface is found to consist of bare copper, indicating
etching of the overlying graphene. The inability to form h-BN layers on top of
graphene is discussed in terms of the catalytic behavior of the underlying
copper surface and the decomposition of the borazine on top of the graphene.
