A new type of gas sensor based on thermionic charge carrier emission

This paper presents investigations on DC emission currents from heated surfaces at ambient pressure for the purpose of gas sensing. Since applied gases alter the work function (WF) of a material, the emitted electron current changes and becomes gas sensitive. Gas sensitive effects were identified as being dependent upon the emission material used. In contrast to vacuum conditions, additional effects arise from interactions among electrons, ions and atoms. Consequently, the electrical behaviour at atmospheric pressure is completely different. This paper presents preliminary results on this new gas sensing principle with materials such as barium nitrate and scandium oxide.