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Proceedings Paper

Thin-film electrodes for trace metal analysis by dc resistance changes
Author(s): Michael J. Schoening; O. Glueck; Peter Kordos; Hans Lueth; H. Emons
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Paper Abstract

The lateral d.c. resistivity of thin metal films with layer thicknesses of less than 30 nm is increased due to the adsorption of certain particles and is decreased by their desorption. The contribution of the adatoms to the film resistivity can be understood similarly to the effect of foreign atoms in a bulk metal. The magnitude of the resistivity increase is related to the surface coverage of the thin metal film. Using thin metal films of gold as working electrodes in a conventional three-electrode arrangement, a novel electrochemical microsensor, based on the described mechanism of the surface resistivity changes has been developed. The thin film sensor has been prepared by means of process steps of silicon planar technology. With this sensor the trace analysis of heavy metals, such as cadmium, lead, nickel, thallium, and zinc ions as well as cadmium-EDTA complexes in aqueous solutions is possible. The different species could be distinguished from each other due to their characteristic stripping potentials. For the investigated species a linear signal relation has been obtained over a wide range of concentrations from several ppb to some ppm.

Paper Details

Date Published: 18 November 1999
PDF: 9 pages
Proc. SPIE 3857, Chemical Microsensors and Applications II, (18 November 1999); doi: 10.1117/12.370279
Show Author Affiliations
Michael J. Schoening, Research Ctr. Juelich (Germany) and Univ. of Applied Sciences (Germany)
O. Glueck, Research Ctr. Juelich (Germany)
Peter Kordos, Research Ctr. Juelich (Germany)
Hans Lueth, Research Ctr. Juelich (Germany)
H. Emons, Research Ctr. Juelich (Germany)

Published in SPIE Proceedings Vol. 3857:
Chemical Microsensors and Applications II
Stephanus Buettgenbach, Editor(s)

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