Regensburg 2013 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 46: Nanostructures and Clusters
O 46.4: Vortrag
Mittwoch, 13. März 2013, 11:15–11:30, H45
Substrate-dependent dynamics of truly monodisperse Pd clusters under the STM — •Michael König1, Bo Wang1, Yves Fukamori1, Bokwon Yoon2, Friedrich Esch1, Ueli Heiz1, and Uzi Landman2 — 1Chemistry Department, Technische Universitat Munich, 85748 Garching, Germany — 2School of Physics, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
We developed preparing truly monodisperse cluster-assembled materials via deposition of size-selected, soft-landed Pd clusters on epitaxial graphene to enable to fully complement STM with integral methods.
Our STM measurements show that the Pd clusters are well-dispersed on the graphene surface at room temperature (RT). Pd19/Pd20 clusters show both 2 and 3 monolayer high atomic structures, like clusters in the gas phase, but can be distinguished by slightly different height histograms. Neither cluster fragments, nor surface damage are observed, confirming a well-controlled soft-landing on the graphene surface [1].
The clusters on graphene/Ru(0001) are exclusively adsorbed on the ring-fcc registry of the superstructure, indicating a strong carbon-metal interaction and a softening of the carbon-carbon bonding at this local registry. The STM study reveals that the cluster mobility depends on the cluster footprint, e.g. Pd12 clusters show already at RT isomer-dependent diffusion [1]. Finally, the substrate and temperature dependent ripening processes were examined via variable temperature STM. [1]B. Wang, B. Yoon, M. Konig, Y. Fukamori, F. Esch, U.Heiz and U. Landman, Nanoletters 12, 5907 (2012)