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 $1.24 \times 10^{{7}}$ (in 1% H2/air gas at 300 K) and an extremely low detection level (${\le} 1$ ppm H2/air). Furthermore, based on a kinetic adsorption analysis, the activation energy was only 13.1 $\text {KJ}\cdot \text {mol}^{-{1}}$ that is beneficial for hydrogen sensing. The proposed device is therefore promising for high-performance hydrogen sensing applications. [ABSTRACT FROM AUTHOR]