Sensors based on AlGaN/GaN HEMT for fast H2 and O2 detection and measurement at high temperature

Gas sensors based on AlGaN/GaN transistors are fabricated using platinum gate to detect and to quantify 112 (1.5-10%) and O ₂ (1.5-100%) species at high temperature (500 °C). The metrics ΔI/Δt measured within the 5 first seconds of the transient response to the target gas exposure is used to quantify the performance of the sensors. A linear relation between ΔI/Δt and gas concentration is found. ΔI/Δt increases with gas concentration and decreases at high temperature. Sensor sensitivity increases when gas concentration increases. For H ₂ gas, it is noticed that the sensitivity increases when temperature increases. Sensors response and recovery times decrease as gas concentration increases and decrease when temperature decreases.