Regensburg 2000 – wissenschaftliches Programm
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O: Oberflächenphysik
O 19: Epitaxie und Wachstum (IV)
O 19.5: Vortrag
Dienstag, 28. März 2000, 17:15–17:30, H36
Growth of Titanium and Titanium Oxide Films on Re(10-10) — •Dirk Rosenthal, Tamerlan T. Magkoev, Klaus Christmann, and Sven L.M. Schroeder — FU Berlin, Institut für Chemie, Takustraße 3, 14195 Berlin
The growth of ultrathin Ti films and their interaction with oxygen on Re(10-10) have been investigated in UHV by means of photoelectron and ion scattering spectroscopy. At room temperature, Ti films up to a thickness of 2 ML grow in layer which are thermally stable up to 700 K. Annealing to higher temperatures was avoided to prevent Re/Ti alloy formation. For the same reason, Ti films were removed by Ar+ ion sputtering, not by thermal desorption. O2 exposure of the Ti films at pressures around 10−7 mbar results in the formation of chemisorbed and, at elevated temperatures (500 K - 700 K), clusters of varying overall stoichiometry TiOx (x = 1...2). A concomitant decrease of in the Ti 2p3/2 emission intensity indicates coalescence into 3-dimensional oxide islands. Oxide films were subsequently grown to thicknesses at which the Re 4f photoelectron emission was entirely suppressed. Control of the surface oxidation state of such TiOx-films was achieved by heat treatment of Ti metal layers deposited onto the oxide. First results of thermal desorption experiments with carbon monoxide to probe the surface properties of TiOx surfaces with different stoichiometry will be reported.