Regensburg 2002 – wissenschaftliches Programm
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O: Oberflächenphysik
O 40: Oxide und Isolatoren (II)
O 40.3: Vortrag
Freitag, 15. März 2002, 11:45–12:00, H45
Co on thin Al2O3 films grown on Ni3Al(100) — •Vitali Podgursky, Ioan Costina, and René Franchy — Forschungszentrum Jülich, ISG - 3, D - 52425 Jülich
The oxidation of Ni3Al(100) and the deposition of Co were studied by means of Auger electron spectroscopy (AES), low energy electron diffraction (LEED), high resolution electron energy loss spectroscopy (EELS), and scanning tunneling microscopy (STM). The oxidation of Ni3Al(100) surface was performed at 1100 K with an exposure of 2000 L O2. The AES results and the EEL spectra of the oxidized Ni3Al(100) surface show that only Al2O3 is formed. Two hexagonal superstructures of Al2O3 with a lattice constant of 17.2 Å and 54 Å, respectively, were found by STM. Co was deposited at 300 K on the Al2O3 film and shows a Volmer-Weber type of growth. The mean diameter of Co clusters increases from 30 Å for a nominal deposition of 0.1 Å to 40 Å for 1 Å of deposit. For a completely covered surface the mean diameter of Co was 50 Å - 70 Å. The average size of the Co clusters is increased after annealing at 670 K to 100 Å, and to 150 Å for 870 K. Above 700 K, the diffusion of Co through the oxide film into the substrate seems to take place.