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Open AccessArticle

Investigation of Stability and Power Consumption of an AlGaN/GaN Heterostructure Hydrogen Gas Sensor Using Different Bias Conditions

School of Electronic and Electrical Engineering, Hongik University, Seoul 04066, Korea
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Sensors 2019, 19(24), 5549; https://doi.org/10.3390/s19245549
Received: 13 November 2019 / Revised: 4 December 2019 / Accepted: 13 December 2019 / Published: 16 December 2019
(This article belongs to the Section Chemical Sensors)
A Pd-functionalized hydrogen gas sensor was fabricated on an AlGaN/GaN-on-Si heterostructure platform. The AlGaN layer under the Pd catalyst area was partially recessed by plasma etching, which resulted in a low standby current level enhancing the sensor response. Sensor stability and power consumption depending on operation conditions were carefully investigated using two different bias modes: constant voltage bias mode and constant current bias mode. From the stability point of view, high voltage operation is better than low voltage operation for the constant voltage mode of operation, whereas low current operation is preferred over high current operation for the constant current mode of operation. That is, stable operation with lower standby power consumption can be achieved with the constant current bias operation. The fabricated AlGaN/GaN-on-Si hydrogen sensor exhibited excellent sensing characteristics; a response of 120% with a response time of < 0.4 s at a bias current density of 1 mA/mm at 200 °C. The standby power consumption was only 0.54 W/cm2 for a sensing catalyst area of 100 × 24 μm2. View Full-Text
Keywords: AlGaN/GaN heterostructure; hydrogen sensor; power consumption; stability; current mode operation AlGaN/GaN heterostructure; hydrogen sensor; power consumption; stability; current mode operation
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    Doi: https://orcid.org/0000-0003-2855-2723
MDPI and ACS Style

Choi, J.-H.; Kim, H.; Sung, H.-K.; Cha, H.-Y. Investigation of Stability and Power Consumption of an AlGaN/GaN Heterostructure Hydrogen Gas Sensor Using Different Bias Conditions. Sensors 2019, 19, 5549.

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