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MM: Fachverband Metall- und Materialphysik
MM 26: Poster Session
MM 26.74: Poster
Dienstag, 23. März 2010, 14:45–16:30, Poster C
Bucky ball island morphologies on CaF2: Theory and Experiment — •Martin Körner1,2, Felix Loske2,3, Mario Einax1, Angelika Kühnle3, and Philipp Maass1,2 — 1Institut für Physik, Technische Universität Ilmenau, 98684 Ilmenau, Germany — 2Fachbereich Physik, Universität Osnabrück, 49069 Osnabrück, Germany — 3Institut für Physikalische Chemie, Universität Mainz, 55099 Mainz, Germany
Self-organized growth of C60 molecules deposited on insulator substrates such as CaF2(111) yield novel types of morphologies: regular triangular double layers as well as strange irregular islands with hexagonal-type shape, double layer rims at the island edges and channels directed towards the interior of the islands. The relative fraction of the two types of morphologies changes with the temperature. We present a theoretical model to predict these morphologies based on a facilitated de-wetting mechanism of C60 molecules in the first layer in the presence of nearby C60 molecules in the second layer. Extensive Kinetic Monte Carlo (KMC) simulations of this model show good agreement with the experimental observations. In particular they support conjectures from experimental findings that the channel structures of the irregular islands form after deposition. The theory moreover provides an explanation for the regular triangular shapes despite absence of epitaxial matching with the substrate lattice. Detailed consideration of the rates for the diffusion and de-wetting processes in connection with scaling arguments allows us to determine effective energy parameters that govern the growth kinetics in this system.