Chemical routes such as set-gel techniques and thermal decomposition of het
eronuclear complexes have been used to prepare nanosized powders of n-type
(SnO2, TiO2 and In2O3) and p-type (LaFeO3) semiconducting oxides. Thick fil
m gas sensors have been fabricated using these powders, printed on laser pr
e-cut 96% alumina substrates, each 2 X 2 mm element being provided with a h
eater, Au interdigitated contacts and a Pt-100 resistor for controlling the
operating temperature. The films have been fired at different temperatures
suitable to keep the grain size at the nanometer level. Electrical respons
es to some major polluting gases (CO, NO, NO2 and O-3) obtained in the fiel
d have been compared with international standard analytical techniques. (C)
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