Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 31: Nanostructures at surfaces: Dots, particles, clusters, arrays II
O 31.3: Vortrag
Dienstag, 15. März 2011, 11:45–12:00, WIL C107
Catalytic Pt Nanoparticles on GaN Surfaces: In-situ Characterization of Nanoparticle-Support Interaction via High-pressure Synchrotron XPS — •Susanne Schaefer1, Sonja Wyrzgol2, Ian Sharp1, Andreas Jentys2, Detre Teschner3, Axel Knop-Gericke3, Johannes Lercher2, and Martin Stutzmann1 — 1Walter Schottky Institut, Technische Universität München, Garching, Germany — 2Catalysis Research Centre, Technische Universität München, Garching, Germany — 3Fritz-Haber- Institut, Max-Planck-Gesellschaft, Berlin, Germany
Pt nanoparticles on GaN surfaces are investigated as a model system for the electronic control of catalytic reactions at the surface of a wide band gap semiconductor. In the synchrotron XPS study reported here, the electronic interaction of platinum nanoparticles with GaN surfaces was investigated with regard to semiconductor band bending as well as the chemical state of the nanoparticles due to charge transfer processes. Four nanoparticle geometries were tested on both, n-type and p-type GaN surfaces. All samples were measured at room temperature under vacuum and at 200°C, under oxygen, under hydrogen, under hydrogen/ethene (reaction gas, mixture 10:1), and in vacuum after gas exposure. Generally, the nanoparticles exhibited three Pt species, with varying relative intensities, depending on the nanoparticle geometry and substrate doping. From the presented results, we conclude a strong substrate-nanoparticle interaction, which depends on the GaN doping and band bending, as well as on the generation of electron-hole pairs under intense synchrotron illumination.