Hydrogen sensing characteristics of a Pd/AlGaOx/AlGaN-based Schottky diode

Hydrogen sensing characteristics of a Pd/AlGaOx/AlGaN-based Schottky diode-type sensor are comprehensively studied. The AlGaOx dielectric layer is formed by an appropriate hydrogen peroxide (H2O2) treatment on the surface of the AlGaN layer. Experimentally, an extremely high hydrogen sensing response of 3.85 × 105 (under an introduced 1% H2/air gas) and a very low detection limit of 1 ppm H2/air gas are obtained at 300 K. This enhanced sensing performance is mainly caused by the effective dissociation of hydrogen molecules based on the presence of the AlGaOx layer. A response (recovery) time constant of 33(17) s is found upon exposure to 1% H2/air gas at 300 K. The influence of humidity on the hydrogen sensing performance is studied in this work. Based on the improved properties, the studied device could serve as a candidate for high-performance hydrogen sensing applications.