Original scientific paper
Photon-stimulated desorption of hydrogen ions from semiconductor surfaces: evidence for direct and indirect processes
M. Petravić
; Department of Electronic Materials Engineering, Research School of Physical Sciences and Engineering, The Australian National University, Canberra ACT 0200, Australia
A. Hoffman
; Chemistry Department and The Solid State Institute, Technion, Haifa 32000, Israel
G. Comtet
; Laboratoire pour l'Utilisation du Rayonnement Electromagnétique (LURE), Bâtiment 209 D, Université de Paris-Sud, 91405 Orsay Cedex, France
L. Hellner
; Laboratoire de Photophysique Moléculaire, CNRS, Bâtiment 213, Université de Paris-Sud, 91405 Orsay Cedex, France
G. Dujardin
; Laboratoire de Photophysique Moléculaire, CNRS, Bâtiment 213, Université de Paris-Sud, 91405 Orsay Cedex, France
Abstract
Photon-stimulated desorption of positive hydrogen ions from hydrogenated diamond and GaAs surfaces have been studied for incident photon energies around core-level binding energies of substrate atoms. In the case of diamond surfaces, the comparison between the H+ yield and the near edge X-ray absorption fine structure (NEXAFS) for electrons of selected kinetic energies reveals two different processes leading to photodesorption: an indirect process involving secondary electrons from the bulk and a direct process involving core-level excitations of surface carbon atoms bonded to hydrogen. The comparison of H+ photodesorption and electron photoemission as the function of photon energy from polar and non-polar GaAs surfaces provides clear evidence for direct desorption processes initiated by ionisation of corresponding core levels of bonding atoms.
Keywords
desorption of positive hydrogen ions; photon-stimulated; hydrogenated diamond surface; GaAs surface; photon energies around core-level; direct and indirect processes
Hrčak ID:
301020
URI
Publication date:
3.10.1999.
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