Regensburg 2013 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 76: Focussed Session: Solid-liquid Interfaces II

O 76.5: Vortrag

Donnerstag, 14. März 2013, 17:45–18:00, H31

Quantitative void detection in thin platinum films by electrochemical means — •Michael Scheele, Damian Bürstel, and Detlef Diesing — Universität Duisburg - Essen, Fakultät für Chemie, Universitätsstrasse 2, D - 45141 Essen, Germany

In modern catalysis and energy conversion technologies thin metal films (10 - 100 nm) deposited on different substrates are widely used. The wetting of the substrate by the metal during the deposition is crucial for the formation of voids and islands in the thin metal film. Due to a different catalytic behavior of small metal islands (nanoparticles) and different chemical behavior of the substrate (corrosion) the absence of voids and islands is desirable in most cases. A 10 nm thin platinum film is prepared on a substrate consisting of tantalum covered with an ultrathin tantalum oxide film (5 nm). Cyclovoltammetric experiments on the thin platinum film are carried out in sulfuric acid. Although platinum films show a quite good wetting behavior on the oxide, small fractions of uncovered substrate area can show up during preparation or in the electrochemical experiments. The high capacitance of the liquid-oxide-tantalum interface in the voids of the platinum film can be used to measure the charging current of the interface. Hereby the fraction of the substrate which is in contact with the electrolyte and not with the platinum can be estimated. The result indicates that this method is a good way for in-situ detection of uncovered area fractions down to 10^-3 of an 10 nm thick platinum film during surface reactions in liquid media.