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A lean-burn oxygen sensor consisting of a dual-disc semiconductor

1988; Elsevier BV; Volume: 14; Issue: 4 Linguagem: Inglês

10.1016/0250-6874(88)80022-2

1873-3050

Yasuhiro Shimizu, Yoshiki Fukuyama, Chunying Yu, Hiromichi Arai,

Gas Sensing Nanomaterials and Sensors

The oxygen sensitivity of SrTiO3 doped with Al2O3 was sufficiently high in the lean-burn region. However, the usefulness of these specimens as oxygen sensors was limited by the fact that a transition into n-type semiconductivity appeared in the vicinity of the stoichiometric point of air-fuel combustion, due to the small value of the solubility limit of Al2O3 in SrTiO3. On the other hand, Cr2O3 retained p-type semiconductivity even in the richburn region. Thus the properties of a dual-disc semiconductor device made by electrically contacting discs of Sr0.99Al0.01O3 — δ and Cr2O3 in series with a platinum mesh were investigated for use as a lean-burn oxygen sensor. The SrTi0.99Al0.01O3 — δ/Cr2O3 device exhibited a large change in resistance in the lean-burn region and a negligible change in the rich-burn region. Furthermore, the device had a good reproducibility of operation and a short response time of less than 400 ms. These results have proved that the device is useful for a lean-burn oxygen sensor.