Hydrogen Sensing Properties of FET-Type Sensors with Pt-In2O3 at Room Temperature

Abstract

In this paper, a field effect transistor (FET)-type sensor with Pt-decorated In2O3 (Pt-In2O3) nanoparticles is fabricated for detecting H2 gas at room temperature. A pulsed measurement method is adopted to continuously alternate between pre-biasing the gate and reading the drain current of the FET-type sensor. This method effectively reduces the drift in the sensing signal. It is also found that negative pre-bias voltages can dramatically shorten the recovery time of the sensor after sensing H2, while positive pre-bias voltages have the opposite effect. The H2 sensing performance of the sensor is characterized under the enhancement of a pulsed negative pre-bias. By calculating and comparing the root mean square, signal-to-noise ratio, and detection limit of the sensor under different operating regions, it is found that the sensor has the best sensing performance in the subthreshold region, which is suggested to be the optimum operating region for FET-type sensors. In addition, the presence of oxygen significantly consumes the hydrogen molecules and reduces the room-temperature H2 sensitivity of the sensor. The proposed sensor presents promising H2 sensing properties, and this research could be a guide for the use of FET-type sensors in more gas detection applications.