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FIZIKA A 8 (1999) 4 , 275-284
 
PHOTON-STIMULATED DESORPTION OF HYDROGEN IONS FROM SEMICONDUCTOR
SURFACES: EVIDENCE FOR DIRECT AND INDIRECT PROCESSES
M. PETRAVIÆa,A. HOFFMANb, G. COMTETc,
L. HELLNERd and G. DUJARDINd
aDepartment of Electronic Materials Engineering, Research
School of Physical Sciences and Engineering, The Australian National University, Canberra
ACT 0200, Australia
bChemistry Department and The Solid State Institute,
Technion, Haifa 32000, Israel
cLaboratoire pour l'Utilisation du Rayonnement
Electromagnétique (LURE),
Bâtiment 209 D, Université de Paris-Sud, 91405 Orsay Cedex, France
dLaboratoire de Photophysique Moléculaire, CNRS, Bâtiment
213,
Université de Paris-Sud, 91405 Orsay Cedex, France
Dedicated to Professor Boran Leontiæ on the occasion of his 70th
birthday
Received 22 November 1999; revised manuscript received 21 February 2000
Accepted 3 April 2000
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.
PACS numbers: 79.20.La, 79.70.+q
UDC 531.743.56
Keywords: desorption of positive hydrogen ions, photon-stimulated, hydrogenated diamond
surface, GaAs surface, photon energies around core-level, direct and indirect processes
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