Pt-AlGaN/GaN HEMT-Sensor for Hydrogen Sulfide

AlGaN/GaN high electron mobility transistor (HEMT)-sensor with a catalytic Pt-gate is fabricated and tested for toxic H2S gas detection. AlGaN/GaN was chosen to extend the sensor detection range and to be able to operate at temperatures beyond those allowed by state-of-art Si-FET sensors. Testing was performed using a gas mixing apparatus in dry synthetic air ambient. High sensitivity, ΔI/I0, 8% for 80 ppm and 0.23% for 0.5 ppm H2S/air, is achieved at a temperature of 250 °C, with a corresponding ΔI of 617 μA and 18 μA, respectively, indicating suitability of the proposed sensor for industrial gas safety detectors.