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O: Oberflächenphysik
O 8: Epitaxie und Wachstum (II)
O 8.8: Talk
Monday, March 27, 2000, 18:00–18:15, H36
Combined photoluminescence and high resolution electron energy loss spectroscopy study of the formation of ultrathin SiOx on Si(100)-2x1 — •Thomas Bitzer1, Neville Richardson1, Thomas Dittrich2, and Fred Koch2 — 1University of St. Andrews, School of Chemistry, St. Andrews KY 16 9ST, U.K. — 2Technische Universität München, Physik Department E16, D-85748 Garching, Germany
The formation of ultrathin SiOx on Si(100)-2x1 is studied
by photoluminescence (PL) and high resolution electron energy
loss spectroscopy. The radiative band to band recombination of
the bulk Si is limited by the nonradiative (nr) surface
recombination. The PL intensity of the c-Si bulk with the
Si(100)-2x1 surface is comparable to that covered with a native
oxide, i.e. the concentration of the nr surface defects is in
the order of 1012 cm−2. The PL intensity is
insensitive to the dissociative adsorption of water molecules
but decreases even for very small dosages of oxygen (below
0.005 L). New nr surface defects arise only from the oxidation
of Si surface atoms which includes the breaking of Si backbonds.
The new nr surface defects can be partially passivated by
dissociative adsorption of water molecules. Our experiments
show that the silicon dangling bonds at the ideally
reconstructed Si(100)-2x1 surface are not recombination active.