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/GaO
_x
/ GaN-based metal-oxide-semiconductor diode hydrogen sensor is fabricated and studied. In this paper, appropriate photochemical drop coating and an H
₂
O
₂
surface treatment were used to form Pd NPs and a GaO
_x
dielectric layer. The Pd NPs increased the surface area/volume ratio, and the presence of GaO
_x
layer led to the effective dissociation of hydrogen molecules. The improved hydrogen sensing properties include a very high sensing response of 1.24 × 107 (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.