Hydrogen Detection Performance of a Pt-AlGaN/GaN HEMT Sensor at High Temperatures in Air Ambient

Abstract

A Pt-gated AlGaN/GaN high electron mobility transistor (HEMT) was fabricated and used for sensing hydrogen (H2) gas in air ambient at extreme temperatures. Compared to previous studies, this work extends the investigation of GaN HEMT device H2 detection capabilities to temperatures as high as 450℃ in air background. The performance of the device was comprehensively demonstrated and analyzed over a wide temperature range from 200 to 450℃. To begin with, an optimum operating drain-source (Vds) and gate-source voltages (Vgs) were found as 4.5 and 0 V, respectively. At this bias, the sensor demonstrated the highest sensitivity (28.19 %) in conjunction with fast response (48.62 s), and recovery time (109.48 s) at 450℃. The impact of temperature on sensitivity, response, and recovery time was also discussed, revealing that sensitivity ranged from 24.9 to 28.2% between 250 and 450℃, which is significantly higher than the sensitivity at 200℃ (18.8 %). Additionally, response times under 50 s were obtained from 350 to 450℃, with the lowest being 39.54 s at 400℃. Furthermore, the signal-to-noise ratio consistently exceeded 30 dB across the temperature range of 250 to 450℃. Finally, the first-derivative method, utilized for assessing the triggering capability of the sensor, revealed peak performance at 300℃