Dresden 2006 – scientific programme
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O: Oberflächenphysik
O 48: Nanostructures IV
O 48.4: Talk
Friday, March 31, 2006, 12:00–12:15, WIL A317
Scanning Tunneling Microscopy (STM) and Spectroscopy (STS) Investigations of Gold Nano-Particles in a Double-Tunneling-Junction Arrangement at Room-Temperature — •Anna Tschetschetkin, Christof Dietrich, Berndt Koslowski, and Paul Ziemann — Abteilung Festkörperphysik, Universität Ulm, D-89069 Ulm
Au nano-particles were prepared on an epitaxial Al2O3/Nb(110)/Sapphire layered system employing a micellar technique. This type of arrangement was analyzed by STM and STS at room temperature in ultra-high vacuum. For the as-prepared Au nanoparticles, STM shows an inhomogeneous surface of the particles while STS reveals Coulomb charging for about 60-70% of the particles if the tip is positioned at their apex. However, quantitatively the Coulomb gap is unexpectedly large and it depends sensitively on the tip position above the particle. By annealing the samples at temperatures up to 800∘C, the surface of the particles becomes more homogeneous and is partly faceting, the Coulomb gap decreases, and its value becomes less sensitive to the tip position. The data then can be analyzed in terms of orthodox Coulomb blockade theory.