P. Ma et Aj. Slavin, INITIAL OXIDATION OF ULTRATHIN ANTIMONY FILMS ON AU(111) AND OF POLYCRYSTALLINE ANTIMONY, Physical review. B, Condensed matter, 49(12), 1994, pp. 8340-8346
It has been shown previously that antimony evaporated onto a Au(111) s
urface grows in a layer-by-layer mode. The present work compares the i
nitial, fast-oxidation stage of these films with that on bulk polycrys
talline antimony. Measurements were carried out in an ultrahigh-vacuum
environment using Auger electron spectroscopy, low-energy electron di
ffraction, electron-energy-loss spectroscopy, and work-function change
measurements. At 300 K and for oxygen pressures between 1 X 10(-5) an
d 2 X 10(-3) Torr, oxidation follows first-order Langmuir kinetics, wi
th an initial sticking probability of about 10(-5). Oxidation essentia
lly saturates by 10(7) L (1 L = 10(-6) Torr s). A layer of oxide about
8.5 angstrom thick is formed in this initial stage, both for Sb films
and for bulk antimony. An initial antimony film on Au(111) of about 1
.7 monolayers, or 1.6 X 10(15) atoms/cm2, is required to complete this
oxide layer, for saturation oxidation. The chemical composition of th
e oxidized films and the oxidized surface of bulk antimony is Sb2O3. T
hese results are compared with earlier work on Pb, Bi, and Sn.