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O: Oberflächenphysik

O 28: Postersitzung (Elektronische Struktur, Grenzfläche fest-flüssig, Halbleiteroberflächen und -grenzflächen, Magnetismus und Symposium SYXM, Methodisches, Nanostrukturen, Oberflächenreaktionen, Teilchen und Cluster, Zeitaufgelöste Spektroskopie)

O 28.44: Poster

Mittwoch, 10. März 2004, 16:00–19:00, Bereich C

Metal-on-insulator nanostructures via surface color centers — •Svend Vagt, Tammo Block, Volkmar Zielasek, and Herbert Pfnür — Institut für Festkörperphysik, Universität Hannover, Appelstr. 2, 30167 Hannover

We present first experimental results obtained in a pursuit of a new type of electron beam nanolithography in UHV that is based on the generation of surface color center patterns on epitaxial insulator films and the selective nucleation of metal islands. Experiments were performed in a combined system of an SEM (1-25 keV, resol. 4 nm) and a confocal variable temperature STM (80-900 K). Epitaxial NaCl layers on Ge(100) (up to 6 ML thick) were irradiated by the electron beam of the SEM under varying doses. EELS and scanning Auger microscopy showed the generation of color centers and Na clusters and colloids associated with electron-induced desorption of Cl in the irradiated areas. The NaCl films turned out to be extremely sensitive to a 3 keV electron beam and due to high surface mobility of Na metal clusters formed easily. After high e-beam exposure STM at 2 monolayer thick NaCl layers revealed the formation of beam-induced line-shaped gaps in the film down to the substrate. Depending on the electron dose, a width down to 35 nm was observed, probably limited by secondary electrons. Deposition of Ag on the surface leads to metal aggregation in the center of the gaps, presently being investigated by STM and SEM. The underlying physical mechanisms as well as the potential use of this type of nanostructuring technique and possible refinements will be discussed.