Performance Optimization of Nitrogen Dioxide Gas Sensor Based on Pd-AlGaN/GaN HEMTs by Gate Bias Modulation

Van Cuong Nguyen; Kwangeun Kim; Hyungtak Kim

doi:10.3390/mi12040400

Performance Optimization of Nitrogen Dioxide Gas Sensor Based on Pd-AlGaN/GaN HEMTs by Gate Bias Modulation

Micromachines (Basel). 2021 Apr 5;12(4):400. doi: 10.3390/mi12040400.

Authors

Van Cuong Nguyen¹, Kwangeun Kim², Hyungtak Kim¹

Affiliations

¹ School of Electronic and Electrical Engineering, Hongik University, Seoul 04066, Korea.
² School of Electronics and Information Engineering, Korea Aerospace University, Gyeonggi 10540, Korea.

Abstract

We investigated the sensing characteristics of NO₂ gas sensors based on Pd-AlGaN/GaN high electron mobility transistors (HEMTs) at high temperatures. In this paper, we demonstrated the optimization of the sensing performance by the gate bias, which exhibited the advantage of the FET-type sensors compared to the diode-type ones. When the sensor was biased near the threshold voltage, the electron density in the channel showed a relatively larger change with a response to the gas exposure and demonstrated a significant improvement in the sensitivity. At 300 °C under 100 ppm concentration, the sensor's sensitivities were 26.7% and 91.6%, while the response times were 32 and 9 s at V_G = 0 V and V_G = -1 V, respectively. The sensor demonstrated the stable repeatability regardless of the gate voltage at a high temperature.

Keywords: gallium nitride; gate bias modulation; high electron mobility transistor; nitrogen dioxide gas sensor; palladium catalyst.

Abstract

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