Semiconducting direct thermoelectric gas sensors

Key words gas sensor, thermopower, thermoelectric, simulation, tin oxide. 

This introductory section will describe the various issues that are motivating research on direct thermoelectric gas sensors before presenting a brief introduction to thermoelectric power for the general reader. The principles of direct and indirect thermoelectric gas sensors are then outlined, while early research work is reviewed in the final subsection. 

Gas sensors play an important role in many applications, and have been extensively developed during the past few decades. This is especially the 

Semiconducting direct thermoelectric gas sensors (DTEGs) do not have the disadvantages of resistive or potentiometric gas sensors. The measurand 

The intention of this section is to give the inexperienced reader a short introduction to the physical background of thermopower, also known as thermoelectric power . The reader is referred to Thermoelectricity (Heikes and Ure, 1961), for a more detailed analysis. 

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The direct thermoelectric gas sensors introduced in the preceding sections were based on semiconducting oxide materials. However, other materials besides electronic conductors can be employed as materials for DTEGs. Several years ago, it was shown that the thermopower p of an electrochemical cell with Ft electrodes separated by an oxygen ion conductor follows Equation [7.23] (e.g. Ahlgren and Poulsen, 1995) ... 

Rettig F, Moos R (2007b) Direct thermoelectric hydrocarbon gas sensors based on SnO. IEEE Sens J 7 1490-1496 Rettig F, Moos R (2008) Morphology dependence of thermopower and resistance in semiconducting oxides with space charge regions. Solid State Ionics 179 2299-2307... 

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