Understanding the fundamental principles of metal oxide based gas sensors; the example of CO sensing with SnO2 sensors in the presence of humidity

This paper investigates the effect of water vapour in CO sensing by using Pd doped SnO2 sensors realized in thick film technology as an example of the basic understanding of sensing mechanisms applied to sensors. The results of phenomenological and spectroscopic measurement techniques, all of them o...

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Bibliographic Details
Published in:	Journal of physics. Condensed matter 2003-05, Vol.15 (20), p.R813-R839
Main Authors:	Bârsan, N, Weimar, U
Format:	Article
Language:	eng
Subjects:	Analytical chemistry Chemistry Exact sciences and technology General equipment and techniques General, instrumentation Instruments, apparatus, components and techniques common to several branches of physics and astronomy Physics Sensors (chemical, optical, electrical, movement, gas, etc.) remote sensing
Online Access:	Get full text
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Summary:	This paper investigates the effect of water vapour in CO sensing by using Pd doped SnO2 sensors realized in thick film technology as an example of the basic understanding of sensing mechanisms applied to sensors. The results of phenomenological and spectroscopic measurement techniques, all of them obtained under working conditions for sensors, were combined with modelling in order to derive conclusions able to be generalized to the field of metal oxide based gas sensors. The techniques employed were: do conductance, ac impedance spectroscopy, work function (by using the Kelvin probe method), catalytic conversion and diffuse reflectance infrared Fourier transform measurements. The most important conclusion is that the different parts of the sensor (sensing layer, electrodes, substrate) are all influencing the gas detection and their role has to be taken into consideration when one attempts to understand how a sensor works.
ISSN:	0953-8984 1361-648X