Dresden 2009 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 42: Interfaces/surfaces

HL 42.3: Vortrag

Donnerstag, 26. März 2009, 10:00–10:15, POT 51

Application of catalytic nanoparticles to wide bandgap semiconductor surfaces — •Susanne Schaefer¹, Sonja Wyrzgol², Yizhen Wang¹, Johannes Lercher², and Martin Stutzmann¹ — ¹Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching, Germany — ²Technische Chemie 2, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany

Wide bandgap semiconductors are investigated as materials for the electronic control of catalytic reactions via metal nanoparticles. To conduct test reactions like selective hydrogenation, platinum nanoparticles are applied to the semiconductor surface. GaN substrates, which were grown by MOCVD as well as PAMBE, were used as nanoparticle support. The nanoparticles were prepared by two methods: spin-coating with polymer-encapsulated Pt nanoparticles and evaporation of Pt at elevated temperatures. For polyvinyl-pyrolidone (PVP)-coated nanoparticles, an avarage size of 2.4 nm was observed with TEM. The PVP-coated particles were applied to the semiconductor support via spin coating and activated by oxygen plasma. For particles applied by evaporation, Pt layers with a nominal thickness of 0.2-5 nm were deposited, as determined by EDX. Under defined heating and gas flow, the platinum atoms coalesce to particles. Particle sizes and distributions were investigated with AFM. For testing the electronic properties of these semiconductor-metal interfaces, Schottky diodes were processed with standard lithography. UI-characteristics were measured for various particle sizes.