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

Abstract

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. Keywords—HEMT, sensors, GaN, H2, O2, NO2, NO, NH3 high temperature, highly porous gate.