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

International audienceGas sensors based on AlGaN/GaN transistors are fabricated using platinum gate to detect and to quantify H2 (1.5-10%) and O2 (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 H2 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