Group-III-Nitride Based Gas Sensing Devices

Abstract

The paper reports on novel gas sensing devices based on III-nitride materials. Both platinum GaN Schottky diodes as well as high-electron-mobility transistors formed from GaN/AlGaN heterostructures with catalytically active platinum gates were investigated. The performance of these devices towards a number of relevant exhaust gas components (H2, HC, CO, NO) was tested. The test gas concentrations as well as the composition of background gases were chosen to simulate exhaust gas emissions from lean-burn engines. We found that GaN-based devices with platinum electrodes are mainly sensitive to hydrogen and unsaturated hydrocarbons with a sizeable cross-sensitivity to CO. Furthermore a strikingly dissimilar gas sensing behavior has been observed with respect to saturated hydrocarbons on the one hand and to hydrogen and unsaturated hydrocarbons on the other hand.