Abstract: A solid-state, multi-stage gas detector for detecting a selected gaseous species from a plurality of gaseous species. The multi-stage gas detector includes a first conductive layer, exposable to the plurality of gaseous species, which permits the selected gaseous species to diffuse therethrough and which interacts with at least one of the plurality of gaseous species such that its conductivity changes. A second conductive layer, electrically isolated from the first conductive layer, interacts with the selected gaseous species after it has passed through the first conductive layer such that the second conductive layer's conductivity changes in relation thereto. Electrodes are attached to the first conductive layer and to the second conductive layer for separate detection of conductivity changes within the conductive layers. Detector conductivity changes comprise detection information correlated to the selected gaseous species.

Abstract: A device for detecting a gaseous species including (i) a silicon substrate having two major surfaces and comprising a dielectric window region (ii) a heater situated on the dielectric window region on one major surface; and (iii) a conductivity cell electrode thin metal transducing film assembly situated on the dielectric window region on the other major surface is disclosed. The thin transducing film contacts the conductivity cell electrode.