High-Sensitivity Hydrogen Sensor Based on AIGaN/GaN Heterojunction Field-Effect Transistor

초록

We have developed a Pd-functionalized hydrogen gas sensor based on a recessed AlGaN/GaN heterostructure field-effect transistor. The AlGaN barrier layer under the Pd catalyst was partially etched to enhance its sensitivity. Both low-power consumption and high sensitivity were achieved by employing a recessed structure. Sensor characterization was carried out at the temperature range from room temperature to 250 degrees C, among which the best sensing characteristics were observed at 200 degrees C. A sensitivity of 380% with a response time of 0.25 s was achieved at a bias voltage of 0.3 V at 200 degrees C under a hydrogen exposure concentration of 4%. The standby power consumption was only 2 mu W for the sensing area of 100 x 28 mu m(2) due to the low standby current, which was caused by the recessed AIGaN barrier layer.

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