We developed a dual-gate field-effect transistor (FET) hydrogen gas sensor for application to hydrogen vehicles. The dual-gate FET hydrogen sensor was integrated with a Pt-gate FET to detect hydrogen and a Ti-gate FET as the reference sensor in the same Si chip. The Ti-FET had the same structure as the Pt-FET except for the gate metal. The Pt-FET showed a good response to hydrogen gas above 10 ppm in air, while the Ti-FET did not show any response to hydrogen gas. The differential output voltage between the Pt-FET and the Ti-FET was stable in the temperature range from room temperature to 80 °C because of the same temperature dependence of the current–voltage (I–V) characteristics. In addition, the temperature of the integrated hydrogen sensor was controlled by an integrated system consisting of a heater and a thermometer at any given temperature under severe weather conditions.

We developed a dual gate FET hydrogen gas sensor for application to hydrogen vehicles. The dual gate FET hydrogen sensor was integrated with Pt-gate FET to detect hydrogen and Ti-gate FET as the reference sensor in the same Si chip. Ti-gate FET has the same structure as Pt-FET except for the gate metal. The Pt-FET showed good response to hydrogen gas above 10 ppm in air, while the Ti-FET did not show any response to hydrogen gas. The differential output voltage between the Pt-FET and the Ti-FET was stable in the range of room temperature to 80˚C because of the same temperature dependence of the I-V characteristic.

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