Identification of the 6H-SiC(0001) 3 x 3 surface reconstruction core-level shifted components

We investigate the 6H-SiC(0001) 3 x 3 surface reconstruction by Si 2p and Cls core-level photoemission spectroscopy using synchrotron radiation providing the first identification of surface core-level shifted components. Specific spectral features at the Si 2p core level, including bulk (B) and two surface shifted (SS1 and SS2) components, show a surface reconstruction structure involving several silicon atomic planes. In comparison, the C Is core level shows no involvement of carbon atoms in the 6H-SiC(0001) 3 x 3 surface reconstruction structure. These results, obtained by an attenuation layer model, indicate that SS1 is related to the Si adatom and that SS2 is related to the Si adlayer + trimer of the 6H-SiC(0001) 3 x 3 surface reconstruction. (C) 2000 Elsevier Science B.V. All rights reserved.