Enhancement of Hydrogen Sensing Performance of a Pd Nanoparticle/Pd Film/GaOx/GaN-Based Metal-Oxide-Semiconductor Diode

A new Pd nanoparticle (NP)/Pd film/GaOx/GaN-based metal-oxide-semiconductor diode hydrogen sensor is fabricated and studied. In this paper, appropriate photochemical drop coating and an H2O2 surface treatment were used to form Pd NPs and a GaOx dielectric layer. The Pd NPs increased the surface area/volume ratio, and the presence of GaOx layer led to the effective dissociation of hydrogen molecules. The improved hydrogen sensing properties include a very high sensing response of 1.24 x 10(7) (in 1% H-2/air gas at 300 K) and an extremely low detection level (<= 1 ppm H-2/air). Furthermore, based on a kinetic adsorption analysis, the activation energy was only 13.1 KJ . mol(-1) that is beneficial for hydrogen sensing. The proposed device is therefore promising for high-performance hydrogen sensing applications.