High performance GaN-based hydrogen sensors

摘要

The hydrogen sensing characteristics of the catalytic Pd/GaN and Pd/InGaP MS diodes are systematically studied and compared over wide hydrogen concentration and temperature regimes. Experimentally, upon exposing to hydrogen-containing gases, both forward- and reverse-biased currents of both studied devices are substantially increased with increasing the hydrogen concentration. In other words, both studied devices can be operated under applied bipolarly voltages. Furthermore, particularly under very wide hydrogen concentration regimes, the studied Pd/GaN MS diode can withstand higher temperature operation with remarkable forward and reverse sensitivities of hydrogen detection. In addition, due to larger Schottky barrier height lowering effect, the hydrogen adsorption performance for the Pd/GaN MS diode manifests the superior sensitivity of Schottky barrier variation, especially at higher temperature operation. In contrast, the studied Pd/InGaP MS diode offers remarkable shorter response time of hydrogen adsorption process than the Pd/GaN one particularly at lower temperature operation and is suitable for the lower hydrogen concentration detection.