Regensburg 2007 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 44: Poster Session II (Semiconductors; Oxides and Insulators: Adsorption, Clean Surfaces, Epitaxy and Growth; Surface Chemical Reactions and Heterogeneous Catalysis; Surface or Interface Magnetism; Solid-Liquid Interfaces; Organic, Polymeric, Biomolecular Films; Particles and Clusters; Methods: Atomic and Electronic Structure; Time-resolved Spectroscopies)
O 44.33: Poster
Mittwoch, 28. März 2007, 17:00–19:30, Poster C
Dynamics of Metal Nanodroplets — Anja Habenicht1, Paul Leiderer1, Johannes Boneberg1, •Moritz Trautvetter2, Daniel Told2, Christian Pfahler2, Alfred Plettl2, Paul Ziemann2, Michael Kinyanjui3, and Ute Kaiser3 — 1Universität Konstanz, Fachbereich Physik, 78457 Konstanz — 2Universität Ulm, Institut für Festkörperphysik, 89069 Ulm — 3Universität Ulm, Zentrale Einrichtung Elektronenmikroskopie, 89069 Ulm
Liquid metal nanodroplets are generated by a dewetting-induced detachment process: flat metal nanostructures evaporated onto a substrate through colloidal masks or structured by e-beam lithography are illuminated with an intensive ns laser pulse. If heated above the melting point, the liquid structures reduce their surface energy by reforming to spheres. For the small aspect ratios used here this involves a vertical movement of the center of mass and due to inertia the droplets leave the surface. The velocities of the detached nanodroplets are measured with a light barrier technique and compared with the velocity deduced from simple estimations for the dewetting process. Results are shown for different materials, intermediate layers and multilayers. Further we present first results of impact experiments, where the droplets are landed on another substrate. The particles cool down during the flight due to thermal radiation and solidify on the substrate. By catching at different distances, the landing temperature can be varied. Snapshots of different stages of droplet impact are shown. For the latter case, the focused ion beam technique was applied to cut directly through differently formed droplets.