Wireless Hydrogen Sensor Networks Using AlGaN/GaN High Electron Mobility Transistor Based Differential Diodes Sensor

Abstract

We have demonstrated a wireless hydrogen sensing system using commercially available wireless components and AlGaN/GaN High Electron Mobility Transistor (HEMTs) differential sensing diodes as the sensing devices. The active device in the differential pair is coated with 10 nm of Pt to enhance catalytic dissociation of molecular hydrogen, while the reference diode is coated with Ti/Au. Our sensors have a wide range of detection from ppm levels to ~30%, with the added advantages of a very rapid response time within a couple of seconds, and rapid recovery. The sensors have shown good stability for more than 18 months in an outdoor field test.