Na/carbon-rich β-SiC(100) surface: Initial interface formation and metallization

Abstract

We investigate the room temperature interface formation of the Na/carbon-rich β-SiC(100) surface by core level and valence band photoemission spectroscopy using synchrotron radiation. The deposition of a Na layer at saturation coverage results in surface metallization as evident from the presence of plasmon loss features at core levels, and from a Fermi edge building-up in the valence band. Furthermore, large chemical shifts at both C 1s and Si 2p core level indicate reactive interface formation and surface disruption with significant adsorbate–substrate charge transfer. The Na–Si bond establishment leads to subsequent breaking of the C–Si bonds leaving additional C atoms on the surface as carbon/graphite clusters. Exposure of the Na/β-SiC(100) interface to a small amount of oxygen results in the removal of surface metallization.