SI 2P CORE-LEVEL SPECTROSCOPY OF THE SI(111)-(1 X 1)-H AND SI(111)-(1X 1)-D SURFACES - VIBRATIONAL EFFECTS AND PHONON BROADENING

Very sharp photoemission spectra have been obtained from the Si(111)-( 1 x 1):H and Si(111)-(1 x 1):D surfaces prepared by a simple well-defi ned in situ method. Both the Si 2p core-level spectra and the valence band spectra are essentially identical to spectra reported for the che mically prepared (1 x 1):H surface. We can conclusively exclude contri butions from Si-H(D) stretching vibrational losses to the Si 2p core-l evel spectra, contrary to a recent suggestion. The line shape of the c omponent originating from the surface Si atoms is found to be asymmetr ic, which we assign to asymmetric phonon broadening.