| 摘要 |
PURPOSE:To obtain a gas sensor having good sensitivity, by applying catalysts different in gas selectivity to elements formed by separating an oxide semiconductor into a plurality of sections. CONSTITUTION:An oxide semiconductor (e.g., stannic oxide SnO2)2 is mounted on one surface of an alumina substrate 1 and a heater 3 for heating elements is mounted on the other surface thereof. The oxide semiconductor 2 is one separated into elements 2a, 2b and an electrode 4 is mounted to the element 2a and an electrode 5 to the element 2b and, further, a common electrode 6 is mounted on the elements 2a, 2b. A catalyst (e.g., Pt-Rh-AlO2)7 is applied to the elements 2a and a catalyst (e.g., W-Cu-AlO2)8 to the element 2b. A sensor element A is formed on the basis of the element 2a and the catalyst 7 and a sensor element B on the basis of the element 2b and the catalyst 8. The sensor element A is low in the sensitivity to alcoholic gas and the sensor element B contrarily has good sensitivity to alcoholic gas. The sensor elements A, B have almost equal sensitivities to gas other than alcoholic gas.
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