Structural features of epitaxial graphene on SiC {0001} surfaces

We investigated the atomic-scale structural properties of graphene epitaxially grown on SiC {0 0 0 1} surfaces by high-resolution transmission electron microscope observations. In this review paper, we summarize our results about the interface structure, the growth mechanisms and the growth techniques. Graphene on the Si-terminated surface has a buffer layer that is strongly bonded to the substrate and has a low carbon atom density. Multilayer graphene on the Si-face exhibited an ABC-stacking selectively. Graphene on the Si-face nucleates at the step-edge, and grows layer-by-layer over the upper terrace. Based on the mechanism, we succeeded in growing high-quality and homogeneous monolayer and bilayer graphene on the Si-terminated surface with low-height and low-density steps using our original technique. Graphene on the C-face has weaker bonds with the substrate, and the resulting multilayer contains the rotational stacking disorder. The origin of the rotational stacking is closely related to the growth mechanism, where graphene layers nucleate on a terrace at a lower temperature and grow in all directions on the surface.