Regensburg 2019 – scientific programme
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O: Fachverband Oberflächenphysik
O 68: Poster Wednesday: Nanostructures
O 68.4: Poster
Wednesday, April 3, 2019, 17:45–20:00, Poster B2
Growth and Morphology of Metal Clusters on HOPG — •christophe nacci1, alexander schiffmann2, Florian Lackner2, Philipp Thaler2, Wolfgang E. Ernst2, and Leonhard Grill1 — 1Department of Physical Chemistry, University of Graz, 8010 Graz, Austria — 2Institute of Experimental Physics, TU Graz, 8010 Graz, Austria
Clusters are a unique class of materials with extraordinary electronic, optical, and catalytic properties [1]. Gold nanoparticles are one of the most studied classes of nanoparticles due to their biocompatibility, high chemical and physical stability, the ease of surface functionalization with organic molecules and the optical properties related to surface plasmons. We have produced gold clusters by helium droplet synthesis and deposited them under clean ultrahigh vacuum (UHV) conditions onto an inert HOPG surface, where they were characterized by scanning tunneling microscopy (STM). Extended ramified structures were identified when depositing clusters on the surface kept at room temperature. In particular, the metallic structures exhibit a fractal-like pattern. The temperature dependence of their shapes has been explored by repeated post-deposition thermally annealing: A cross-over from fractal-like to smoother structures could be observed. To shed some light on the growth processes, Au clusters have been further deposited on an HOPG surface exhibiting defects created by ion sputtering in mild conditions.
[1] W. A. de Heer, Rev. Mod. Phys. 65, 611 (1993)