Atomic structure of the 6H-SiC(0001) nanomesh

The atomic structure of the carbon nanomesh template (the so-called 6÷3×6÷3R30° reconstruction) on the 6H-SiC(0 0 0 1) surface was investigated in detail by scanning tunneling microscopy (STM), low energy electron diffraction (LEED), synchrotron photoemission spectroscopy (PES) and density-functional theory (DFT) calculations. We propose that the origin of the carbon nanomesh template arises from the self-organization of excess carbon atoms forming a novel honeycomb arrangement atop the 6H-SiC(0 0 0 1) surface after annealing at 1100 °C. Two carbon nanomesh-related C 1s components are observed at binding energies of 285.1 eV (S1) and 283.8 eV (S 2) by angle-resolved synchrotron PES experiments. We assign the S2 component to carbon atoms that bond to one underlying Si atom, and the S1 component to carbon atoms bonded to other carbon atoms without Si-C bond formation. Further annealing results in the formation of crystalline graphitic layers on top of the surface.