Core-level shifts on clean and adsorbate-covered Si(113) surfaces

The silicon 2p core level was investigated on the Si(113) surface using angle-resolved UV photoelectron spectroscopy and synchrotron radiation. For the clean 3×2 reconstructed Si(113) surface several surface core-level shifts are observed, two of them shifted by 640 meV to lower and 760 meV to higher binding energies, respectively. They are attributed to adatomlike and dimerlike atoms, the main constituents in the Si(113) 3×2 surface structure. A broad component close to the bulk emission is found and is assigned to the other atoms in the two topmost surface layers that are slighty shifted from their bulk position within the reconstruction. By adsorption of atomic hydrogen, these surface components can be quenched and others can be created. Monohydride and dihydride phases are identified.