Berlin 2008 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 18: Poster Session I - MA 141/144 (Atomic Wires; Size-Selected Clusters; Nanostructures; Metal Substrates: Clean Surfaces+Adsorption of Organic / Bio Molecules+Solid-Liquid Interfaces+Adsorption of O and/or H; Surface or Interface Magnetism; Oxides and Insulators: Clean Surfaces)
O 18.14: Poster
Montag, 25. Februar 2008, 18:30–19:30, Poster F
Softlanding and STM imaging of Ag309 clusters on 1 and 2 monolayers C60/HOPG — •L. Patryarcha1, S. Duffe1, T. Richter1, B. Sieben1, H. Hövel1, C. Yin2, B. von Issendorff2, and M. Moseler3,4 — 1Technische Universität Dortmund, Experimentelle Physik I — 2Universität Freiburg, Fakultät für Physik — 3Fraunhofer-Institut für Werkstoffmechanik IWM, Freiburg — 4Freiburg Materials Research Center
At 165 K Ag309 clusters were deposited on HOPG functionalized with C60 and imaged with STM at 77 K. With HOPG at room temperature (RT) during C60 evaporation areas of some 100 nm stayed uncovered, and 2 ML islands were formed on 1 ML C60 planes. On areas with 1 and 2 ML C60 we observed very narrow cluster height distributions with h=(2.4 ± 0.2) nm. By annealing Ag309/C60/HOPG we observed that the cluster height stayed stable for more than 12 h at RT on 1 and 2 ML C60. The clusters on free HOPG areas became mobile during annealing at 265 K and moved to the edges of the C60 areas. The RT stability of Ag309/C60/HOPG is in contrast to the observations for Ag561 and Ag309 on 1 and 2 ML C60/Au(111) which were deposited at 165 K and annealed up to RT. For the samples with an Au(111) substrate we observed that the cluster height on 1 ML C60 decreased and finally all clusters disappeared [1]. Molecular dynamics calculations show that there is a low barrier height for the transport of Ag atoms through the C60 film on 1 ML C60/Au(111) which should be much higher for clusters on 1 ML C60/HOPG.
[1] S. Duffe et al., Eur. Phys. J. D (2007), published online