Hydrogen Sensing Properties of an Aluminum-Doped Zinc Oxide Layer Decorated With Palladium Nanoparticles

A new hydrogen (H ₂ ) sensor based on a sputtered aluminum-doped zinc oxide (AZO) layer decorated with evaporated palladium (Pd) nanoparticles (NPs) was manufactured and studied herein. The use of Pd NPs can efficiently improve the hydrogen gas detecting performance owing to the increased effective surface area, enhanced catalytic reactivity, and spillover effect of noble Pd metal. Energy dispersive X-ray spectroscopy (EDS), atomic force microscopy (AFM), high-resolution scanning microscopy (HRSEM), and transmission electron microscopy (TEM) were employed to investigate the related material properties. Experimentally, good hydrogen gas detection performance, such as a higher sensing response of $1.86\times 10 ^{4}$ under 1% H ₂ /air gas accompanied by a response (recovery) time of 25 s (52 s) and an extremely low detecting content of 50 ppb H ₂ /air at 250°C were acquired from the studied Pd NP/AZO device. The proposed sensor also shows long-term stability related to hydrogen gas.