SYNCHROTRON-RADIATION STUDY OF CS CARBON-RICH BETA-SIC(100) AND CS/SILICON-RICH BETA-SIC(100) SURFACES - METALLIZATION AND INTERFACE FORMATION/

The room temperature interface formation of the Cs/carbon-rich and sil icon-rich beta-SiC(100) single-domain surfaces is studied by core leve l and valence band photoemission spectroscopy using synchrotron radiat ion, For both surfaces, Cs deposition results in reactive interface fo rmation. For the carbon-rich beta-SiC(100), the presence of a Cs monol ayer leads to surface metallization as evident from asymmetric shape t ail at the Cs 4d core level indicating the presence of a plasmon and f rom metal-induced gap state near the top of the valence band. In contr ast, the silicon-rich beta-SiC(100) surface remains semiconducting in presence of a Cs overlayer at saturation coverage, This investigation stresses the central importance of initial surface composition.