Angle-resolved photoemission study of the hydrogenated 3C-SiC(0 0 1)-2×1-H surface

We report the first angle-resolved ultraviolet photoelectron spectroscopy (ARUPS) investigation of the hydrogenated 3C-SiC(0 0 1)-2×1-H surface using synchrotron radiation. The 2×1-H surface was formed by exposing a clean Si-terminated 3C-SiC(0 0 1)-c(4×2) surface to excited hydrogen gas. Desorption of the hydrogen at 900°C led to the restoration of the c(4×2) periodicity. The electronic structure of the 2×1-H surface was investigated with ARUPS along the main symmetry directions of the surface Brillouin zone. A strong hydrogen-induced state was observed in the overlineΓ- J̄^' direction about 4.3 eV below the Fermi energy ( E_F), dispersing slightly downwards. This binding energy (2.4 eV below the valence band maximum ( E_V)) is considerably lower than hydrogen-induced states on Si and Si-rich SiC surfaces, but can be explained by the existence of Si-C backbonds. A second, possibly surface related feature was observed at an energy of 1.9 eV below E_F, in the same direction. These results have significant implications for the question about the atomic structure of the c(4×2) surface. The reversible c(4×2)-2×1 transition and the low binding energy of the H-induced state suggest a model with a single Si monolayer termination.