Paper GR+SS+TF+EM-MoM5
Structural Defects in Epitaxial Graphene Layers Synthesized on 4H-SiC(000-1) Substrate - Transmission Electron Microscopy (TEM) Studies

Monday, October 18, 2010, 9:40 am, Room Brazos

Main structural defects in graphene layers, synthesized on the carbon-terminated face, i.e. SiC(0001) face of 4H-SiC substrate, are discussed. The discussed structures include in-plane edge dislocations, grain boundaries, puckers, etc. These defects are investigated using High Resolution Transmission Electron Microscopy (HRTEM), revealing their atomic arrangement. The mechanism of creation of such defects, in relation to the misalignment to the underlying crystallographic structure of the SiC substrate is elucidated. The relation between the SiC surface structure, including the presence of the single atomic steps, the sequences of atomic steps, and also the macrosteps, and the emergence of edge dislocations or boundaries between the regions having different crystallographic orientation in the graphene layers, is shown. In addition, the structures containing different stacking sequences of carbon atoms in the graphene layers are presented. The presented C-layers stacking includes AA, AB, ABC sequences, and also the stacking close to turbostratic stacking.