Regensburg 2010 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 73: Solid/liquid interfaces II (focussed session)

O 73.5: Vortrag

Donnerstag, 25. März 2010, 16:45–17:00, H33

Electrochemical experiments in sulphuric acid with electronic devices — •Andreas Barmscheid, Damian Bürstel, Eckart Hasselbrink, and Detlef Diesing — Institut für Physikalische Chemie, Universität Duisburg Essen

With chemical experiments on the surfaces of thin film devices one can monitor for example adsorbate induced changes in the film resistivity or the existence of excited charge charriers in the course of a reaction. We show that thin platinum films on Si-SiOx-substrates show a well defined surface chemistry in 0.1 M sulphuric acid. Parts of the eletrochemical charge transfer at the Pt-acid interface can be monitored as a device current flowing from the Pt to the silicon. This transfer ratio depends on the inner potential difference of the device across the SiOx layer as well as on the outer electrode potential across the platinum-sulphuric acid interface. The transfer of charge carriers generated at the platinum-acid interface within the adsorption and desorption reaction of hydrogen is found to have a dependence on the inner device potential which is very similar to that one of photo excited carriers. On the other hand, charge carriers generated during the sulphate adsorption or platinum oxidation reaction do not exhibit similiarities in the transfer through the internal interfaces of the device with photo excited carriers.