| 摘要 |
PROBLEM TO BE SOLVED: To provide a metal oxide material for a semi-conductor sensor for detecting gaseous carbon monoxide stable against the temperature under the environment of hydrogen gas high in concentration by containing indium oxide, zinc oxide, etc., in the metal oxide material of the semi-conductor sensor. SOLUTION: A metal oxide material of a semi-conductor sensor contains indium oxide and zinc oxide, and/or gallium oxide. A material small in resistance change against hydrogen high in concentration, and large in resistance change against carbon monoxide can be obtained, and gaseous carbon monoxide can be selectively detected under the environment of hydrogen high in concentration. In the manufacture of the sensor, a mixed paste of a generated metal oxide is deposited on a ceramic substrate 10. Tip portion of metal electrodes 22, 24 are embedded in a thick film 20 before sintering the paste. The electrodes 22, 24 are connected to a resistance measuring circuit 30 comprising a power source 31 and a current meter 32. In addition, a micro-heater 40 including a resistor 42 in which the power is supplied from a power source 44 is also provided.
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