Angle-resolved photoemission study of the hydrogenated 3C-SiC(001)-2 x 1-Hsurface

We report the first angle-resolved ultraviolet photoelectron spectroscopy ( ARUPS) investigation of the hydrogenated 3C-SiC(0 0 1)-2 x 1-H surface usin g synchrotron radiation. The 2 x 1-H surface was formed by exposing a clean Si-terminated 3C-SiC(0 0 1)-c(4 x 2) surface to excited hydrogen gas. Deso rption of the hydrogen at 900 degreesC led to the restoration of the c(4 x 2) periodicity. The electronic structure of the 2 x 1-H surface was investi gated with ARUPS along the main symmetry directions of the surface Brilloui n zone. A strong hydrogen-induced state was observed in the <(<Gamma>)over bar>-(J) over bar ' direction about 4.3 eV below the Fermi energy (E-F), di spersing slightly downwards. This binding energy (2.4 eV below the valence band maximum (E-V)) is considerably lower than hydrogen-induced states on S i and Si-rich SiC surfaces, but can be explained by the existence of Si-C b ackbonds. A second, possibly surface related feature was observed at an ene rgy of 1.9 eV below E-F, in the same direction. These results have signific ant implications for the question about the atomic structure of the c(4 x 2 ) surface. The reversible c(4 x 2)-2 x 1 transition and the low binding ene rgy of the H-induced state suggest a model with a single Si monolayer termi nation. (C) 2001 Elsevier Science B.V. All rights reserved.