Dresden 2014 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 61: Nanostructures at Surfaces III

O 61.9: Vortrag

Mittwoch, 2. April 2014, 18:00–18:15, WIL B321

Tracking of cluster island diffusion on HOPG using non-contact AFM — Mumin Koç, Gauthier Torricelli, and •Klaus von Haeften — Department of Physics and Astronomy, University of Leicester, UK

Silicon oxide nanoparticles produced by co-deposition of silicon clusters and water vapour show very weak interaction in solution [1,2]. To elucidate the microscopic origins of the weak interaction, we deposited these clusters on highly oriented pyrolytic graphite (HOPG) surfaces and investigated their dynamics using non-contact AFM. The AFM images showed that practically all clusters were agglomerated into islands of different sizes. Larger islands were predominantly immobile, whereas a number of smaller islands were found to perform random walks in a Brownian-motion type fashion. The diffusion constant was determined from the time dependence of the mean square displacement. Detailed inspection of the island dynamics revealed correlated motion of ’dimer-islands’, dissociation, and independent random walks of the dimer fragments. The role of the equipartition of energy between surface, islands, clusters and the AFM tip are discussed.

[1] A. Brewer and K. von Haeften, Appl. Phys. Lett. 94, 261102 (2009). [2] G. Torricelli, A. Akraiam, and K. von Haeften, Nanotechnology 22, 315711 (2011).