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 Γ–J̄′ direction about 4.3 eV below the Fermi energy (EF), dispersing slightly downwards. This binding energy (2.4 eV below the valence band maximum (EV)) 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 EF, 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.