A Highly Porous and Conductive Composite Gate Electrode for NO, NO2, O2, H2 and NH3 Exhaust Gas Sensors

The real-time knowledge of the NO, NO2 and NH3 concentration at high temperature, would allow manufacturers of automobiles to meet the upcoming stringent EURO7 anti-pollution measures for diesel engines. Knowledge of the concentration of each of these species will also enable engines to run leaner (i.e. more fuel efficient) while still meeting the anti-pollution requirements. Our proposed technology is promising in the field of automotive sensors. It based on AlGaN/GaN high electron mobility transistor (HEMT) sensors incorporating highly porous platinum in the gate. Compared to platinum full gate AlGaN/GaN HEMT sensor, the Highly porous gate sensor has dramatically improved current response to O2, NO, NO2 H2 and NH3, to the NO concentration in the range of 0–2000 ppm, 0-2500 ppm NO2, 0-300 ppm NH3, (1.5-10%) H2 and O2 (1.5-100%) species at high temperature (500 °C). This improvement in sensitivity is the result of the increase in catalytic surface area interaction between gas and platinum.