Regensburg 2010 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 52: Heterostructures
HL 52.7: Vortrag
Donnerstag, 25. März 2010, 11:45–12:00, H17
Characterization of catalytic nanoparticle-semiconductor heterostructures by XPS and cyclic voltammetry — •Susanne Schäfer1, Sonja Wyrzgol2, Ian Sharp1, Mehdi Kashani1, Johannes A. Lercher2, and Martin Stutzmann1 — 1Walter Schottky Institut, Technische Universität München, Am Coulombwall 3, 85748 Garching, Germany — 2Catalysis Research Centre, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany
GaN is investigated as a promising material for the electronic control of catalytic reactions via platinum nanoparticles. For all experiments platinum nanoparticles were applied to MOCVD- or MBE-grown GaN substrates by spin coating or physical vapour deposition. Particle size and distribution were investigated with TEM and AFM. The interfacial properties of the catalyst-semiconductor heterostructures were characterized by XPS and cyclic voltammetry. The influence of substrate doping (n-GaN and p-GaN) and morphology (smooth layers and nanowires) were investigated. The detected shifts in Pt4f core levels were correlated to chemical shifts while the shifts in Ga3d, Ga2p and N1s were ascribed to surface band bending in the substrate. Cyclic voltagramms were recorded in darkness and under illumination, as well as with or without a redox couple in the electrolyte. Based on this, devices can be designed for optical as well as electrical excitation of the catalyst-semiconductor system.