Berlin 2005 – wissenschaftliches Programm
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O: Oberflächenphysik
O 36: Postersitzung (Elektronische Struktur, Grenzfl
äche fest-flüssig, Halbleiteroberfl
ächen und -grenzfl
ächen, Nanostrukturen, Oberfl
ächenreaktionen, Teilchen und Cluster, Struktur und Dynamik reiner Oberfl
ächen)
O 36.48: Poster
Montag, 7. März 2005, 15:00–18:00, Poster TU F
Gold Nanoparticles on Nb/Al2O3: An STM Study of Dynamic Charging Effects at Room Temperature — •Christof Dietrich, Berndt Koslowski, Frank Weigl, Hans-Gerd Boyen und Paul Ziemann — Abt. Festkörperphysik, Universität Ulm
In order to obtain a system showing Coulomb Blockade effects at room temperature, in a first step epitaxial Nb(110) films were prepared on Sapphire(0001). These films have an extremely smooth surface (RMS: 0.4 nm for 500x500 nm2) and atomic resolution can be achieved. Onto this base electrode, 0.9 nm of Al was evaporated and oxidized by flashing the sample several times to 1400K in an oxygen atmosphere. An extremely smooth and epitaxial Al2O3 coating was obtained. Small Gold particles (1nm-15nm) were prepared by loading a solution of the diblock-copolymer polystyrene-b-poly(2)vinylpyridin in toluene with HAuCl4. By dip coating, one monolayer of Gold salt loaded inverse micelles could be deposited on the Al2O3/Nb (110)/Sapphire(0001) system. In a final step, the polymer was removed in an Oxygen plasma resulting in naked gold particles of controlled size and separation exhibiting a high degree of hexagonal order as revealed by STM. Additional I-V measurements on the particles clearly show Coulomb blockade effects which can be nicely fit to orthodox theory of the Coulomb blockade. We discuss the effect of annealing on the charging behavior.