The step height is 1.5nm, which corresponds to the dimension of the 6H–SiC unit cell in the direction perpendicular to the surface(c axis).
On defect-free areas of the sample,the terraces typically extend undisturbed over 50µm in length
The morphology of the surface covered with a monolayer of graphene prepared by vacuum annealing is shown in Fig.1b.
The surface obviously undergoes significant modifications;it is now covered with small pits up to 10 nm in depth, and the original steps are hardly discernible any longer