Hydrogen sensing performance of a Pd nanoparticle/Pd film/GaN-based diode

A new Pd nanoparticle (NP)/Pd film/GaN-based Schottky diode-type hydrogen sensor is fabricated and studied. Pd NPs are formed using a proper photochemical approach based on a drop of PdCl2 solution and UV illumination. Experimentally, excellent hydrogen sensing performance, including an extremely high sensing response (4.2 × 106@1% H2/air gas) with a very low detection limit (≤0.8 ppm H2/air) is obtained at 25 °C. This is mainly caused by the enhanced surface area/volume ratio of the Pd NPs and the catalytic reactivity of the Pd film. Furthermore, the studied device exhibits sensitive responses to humid ambiences at 25 °C. Therefore, based on the reported benefits and relatively simple process flow, the studied device is a promising high-performance hydrogen sensor.