Impact of high temperature H-2 pre-treatment on Pt-AlGaN/GaN HEMT sensor for H2S detection

In this paper, a method to extend the detection range of hydrogen sulfide (H2S) gas sensor is demonstrated. The sensor is based on AlGaN/GaN high electron mobility transistors (HEMTs) with Pt gate. It is observed that the as-fabricated devices exhibited sensing signal saturation at 30 ppm H2S exposure in dry air. A pre-treatment using H-2 pulses in dry air ambient at 250 degrees C was applied to extend the detection range of the sensor. The H-2 treated H2S gas sensor was able to detect a higher H2S concentration up to 90 ppm at 250 degrees C without complete saturation.