Sensors based on AlGaN/GaN HEMT for fast H 2 and O 2 detection and measurement at high temperature

Gas sensors based on AlGaN/GaN transistors are fabricated using platinum gate to detect and to quantify H 2 (1.5-10%) and O 2 (1.5-100%) species at high temperature (500 °C). The metrics ∆I/∆t 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 ∆I/∆t and gas concentration is found. ∆I/∆t 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.