Synchrotron radiation study of Cs/carbon-rich β-SiC(100) and Cs/silicon-rich β-SiC(100) surfaces: metallization and interface formation

The room temperature interface formation of the Cs/carbon-rich and silicon-rich β-SiC(100) single-domain surfaces is studied by core level and valence band photoemission spectroscopy using synchrotron radiation. For both surfaces, Cs deposition results in reactive interface formation. For the carbon-rich β-SiC(100), the presence of a Cs monolayer leads to surface metallization as evident from asymmetric shape tail at the Cs 4d core level indicating the presence of a plasmon and from metal-induced gap state near the top of the valence band. In contrast, the silicon-rich β-SiC(100) surface remains semiconducting in presence of a Cs overlayer at saturation coverage. This investigation stresses the central importance of initial surface composition.