Detailed studies of graphene grown on C-face SiC

C. Virojanadara
Linkoeping University, SE

Keywords: graphene, SiC, C-face, stacking


The registry of adjacent graphene layers grown on the C-terminated SiC surface has been reported to be dramatically different compared to graphene grown on the Si-terminated SiC(0001) surface. Whereas Si-face graphene exhibits sharp spots in LEED and the Bernal (ABAB…) stacking, multilayer graphene on the C-face has been reported to stack in such a way that adjacent graphene layers are rotated with respect to each other. It has also been suggested that the rotated layers are interleaved, instead of forming distinct domains of different orientations. The rotational disorder produce moiré patterns in STM topographs, and have been suggested to explain why epitaxial graphene films, tens of layers thick, show single layer electronic properties. We have investigated graphene films furnace grown on the C-face to a thickness varying from 2-3 ML to 6-7 ML utilizing surface science techniques. We find formation of fairly large domains exhibiting sharp (1x1) spots in micro –LEED while adjacent domains are found to show different azimuthal orientations. Macro-LEED patterns collected from several domains mimics earlier recorded and schematically drawn LEED patterns. Our findings indicate that adjacent layers of multilayer graphene grown on the C-face do NOT show the rotational disorder earlier reported.