ATOMISTIC UNDERSTANDING OF SENSOR MECHANISMS - SPECTROSCOPIC STUDIES AT PROTOTYPE ELECTRONIC AND IONIC CONDUCTORS

A brief introduction is given for an unequivocal characterization of geometric, electronic and chemical structures of the different interfaces to be optimized for chemical sensors. These involve the chemically sensitive layers, substrates, contracts, surfaces and passivating overlayers. Systematic concepts are described to characterize these interfaces phenomenologically and spectroscopically with particular emphasis on in situ measurements of atomistic structures under sensor operation conditions. An atomistic understanding about elementary steps of gas/solid interactions is derived which involve one, two and more molecules interacting simultaneously with the sensor. "Prototype" sensor materials discussed here are inorganic electron or mixed conductors (such as ZnO, TiO2, and SnO2), inorganic ion conductors (such as ZrO2 and LaF3) and organic electron or mixed conductors (such as Pb phthalocyanine). The results make possible to build reliable microstructured solid state devices. © 1990.