%0 Journal Article
%T Four-Wire Impedance Spectroscopy on Planar Zeolite/Chromium Oxide Based Hydrocarbon Gas Sensors
%A Gunter Hagen
%A Anne Schulz
%A Matthias Kn£¿rr
%A Ralf Moos
%J Sensors
%D 2007
%I MDPI AG
%R 10.3390/s7112681
%X Impedometric zeolite hydrocarbon sensors with a chromium oxide intermediatelayer show a very promising behavior with respect to sensitivity and selectivity. Theunderlying physico-chemical mechanism is under investigation at the moment. In order toverify that the effect occurs at the electrode and that zeolite bulk properties remain almostunaffected by hydrocarbons, a special planar setup was designed, which is very close to realsensor devices. It allows for conducting four-wire impedance spectroscopy as well as two-wire impedance spectroscopy. Using this setup, it could be clearly demonstrated that thesensing effect can be ascribed to an electrode impedance. Furthermore, by combining two-and four-wire impedance measurements at only one single frequency, the interference of thevolume impedance can be suppressed and an easy signal evaluation is possible, withouttaking impedance data at different frequencies.
%K impedometric gas sensor
%K electrode effects
%K zeolite
%K four-wire impedance spectroscopy
%U http://www.mdpi.com/1424-8220/7/11/2681