New gas sensing mechanism for SnO2 thin-film gas sensors fabricated by using dual ion beam sputtering

A new gas sensing mechanism for SnO2 thin-films fabricated by using dual ion beam sputtering, was proposed. The features of the SnO2 thin-film considered in this study had been characterized as having extremely smooth surface, dense microstructure and near stoichiometric SnO2 phase. In this study, thus, the problems of reported gas sensor models were noticed briefly and next, a novel sensing model for the SnO2 thin-films prepared in this study was approached by geometrical considerations. The effects of resistivity in the bulk regions and in the depletion regions on the gas sensitivities were studied by fabrication of thin-film gas sensors having various film thickness. The proposed gas sensing mechanism was verified by the fabrication of a H2S sensor with p–n junctions.