| 摘要 |
PURPOSE:To suppress time change and humidity dependence in a gas sensor, in which the resistance change in SnO2 is used, by adding fluorine and vanadium into SnO2. CONSTITUTION:Fluorine and vanadium, which are more than impurities, are added into SnO2 constituting a sensor. The desirable amount of the addition of the fluorine is 0.5-100mg per 1g of SnO2 in terms of fluorine atoms. The amount of addition of vanadium is 0.3-10mg per 1g of SnO2 in terms of vanadium atoms. The added fluorine is substituted with the surface hydroxide group of SnO2, and the hydroxide group, which is the main cause of the humidity dependence of the sensor, is decreased. Therefore, the humidity dependence of the sensor can be suppressed. The time change of the sensor is suppressed by the addition of the vanadium. The heating temperature dependence of the sensor is also suppressed. Detecting errors due to the fluctuation in heating temperature can be suppressed. Therefore, the increase in heating temperature dependence, which is the defect of the fluorine, can be compensated with the addition of the vanadium.
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