Improved detection sensitivity of Pt/β-Ga2O3/GaN hydrogen sensor diode

The hydrogen sensing characteristics of Pt/GaN (metal/semiconductor, MS) type and Pt/β-Ga2O3/GaN (metal/reactive insulator/semiconductor, MIS) type hydrogen sensor diodes under hydrogen containing ambience were measured at room temperature. The MIS-type sensor diodes were fabricated in which the β-Ga2O3 oxide layers were directly grown on GaN layer using a photoelectrochemical oxidation method and then annealed in O2 ambience at 700 °C for 2 h. The Pt/β-Ga2O3/GaN sensors exhibited high hydrogen sensing ability. The experimental results demonstrated that the β-Ga2O3 layer played an important role in the MIS-type hydrogen sensor diodes.