High Performance NO2 Gas Sensor Based on Pd-AlGaN/GaN High Electron Mobility Transistors with Thin AlGaN Barrier

Abstract

We investigated the performance of NO2 gas sensors based on AlGaN/GaN high electron mobility transistors (HEMT) with 10 nm AlGaN barrier. The sensors were designed to operate in mu A range to reduce power consumption and realize good sensing performance. The gate area of the HEMT sensor was functionalized using a Pd and Pt catalyst layer for NO2 detection to compare the performance between Pd and Pt catalysts. Pd-functionalized sensors demonstrated better sensing characteristics compared with Pt-functionalized sensors. When the sensors were exposed to 100 ppm of NO2 at 300 degrees C, the relative sensitivity of 53 % was measured with the response time and recovery time of 136 s and 196 s, respectively. Also, the sensor shows a significant change of drain current for 30 s exposure time in different concentrations from 10 to 100 ppm NO2. These results suggest that Pd-AlGaN/GaN HEMT sensors with a thin barrier can be the great choice to detect NO2 gas and they could be used in the harsh environment in real-time condition.