Improved selectivity of oxide semiconductor type gas sensor using compensating element

The selectivity of SnO2 gas sensor for a hydrocarbon gas like i-C4H10 has been improved through the serial connection of a compensating element which is sensitive to the interfering gas. The devices were fabricated in 2 mm x 2 mm through the screen-printing technique. The sensing material, made of SnO2, was doped with Sb2O5 and treated with Pt catalyst to detect a hydrocarbon gas. The compensating material was composed of Sb2O5-doped SnO2 with Pd catalyst to detect interfering gas such as ethanol. The amount of resistance change in each material upon exposure to gas is differed depending on the kind of gas to be exposed, giving rise to an improvement in the selectivity of the device. (C) 2001 Elsevier Science B.V. All rights reserved.