Hydrogen gas sensors are essential for industrial safety, environmental monitoring, and the energy sector. As hydrogen infrastructure expands and hydrogen fuel cell vehicles become more widespread, precise detection of hydrogen, which has a wide explosive range, has become increasingly critical. To ensure accurate detection of hydrogen in real-world conditions, sensor technologies must offer high sensitivity, stability, and reproducibility, along with cost-effectiveness, fast response time, and compact design. This study introduces a hydrogen gas sensor based on pressure analysis principles. This sensor was developed to quantitatively evaluate hydrogen uptake, diffusion behavior, solubility, and release characteristics in polymers under high-pressure conditions. Experimental results demonstrated the sensor’s excellent performance, with a stability of 0.2%, a resolution of 0.12 wt·ppm, and a measurement range of 0.12 to 1500 wt·ppm, all within 1 second. Furthermore, the sensor's sensitivity, resolution, and detection range could be tuned to suit different operational environments. Uncertainty analysis showed an expanded uncertainty of 8.8%, confirming the system’s capability for real-time hydrogen detection and characterization. This sensor technology is well-suited for applications in hydrogen refueling stations and fuel cell systems, contributing to the advancement of a safe hydrogen society.

Gas sensors are crucial devices in various fields such as industrial safety, environmental monitoring, and gas infrastructure. Designed to have high-sensitivity, stability, and reliability, gas sensors are often required to be cost-effective with quick response and compactness. To meet diverse needs, we developed two types of gas sensors based on volumetric and manometric analyses. These sensors could operate by measuring gas volume and pressure changes, respectively, based on emitted gas. These sensors are capable of determining gas transport parameters such as gas uptake, solubility, and diffusivity for gas-charged polymers in a high-pressure environment. These sensors can provide rapid responses within one-second. They can measure gas concentration ranging from 0.01 wt·ppm to 1,500 wt·ppm with adjustable sensitivity and measurement ranges. As a result, such sensor system can be used to facilitate real time detection and analysis of gas transport properties in pure gases including H₂, He, N₂, O₂, and Ar.

Silicon nitride/cobalt tungsten boride (SiN/CoWB) passivation layer improves mass transport rate at copper thin film layers of semiconductor wafers after chemical mechanical polishing process. This study evaluates mass transport at the interface between copper and passivation layers by stress relaxation method, followed by deduction of interface diffusivity via a kinetic model. For comparison, SiN/CoWB, SiN, silicon carbon nitride (SiCN) and silicon carbide (SiC) passivation layers are introduced. A thin layer of SiN/CoWB demonstrates an outstanding performance as diffusion retarding material, especially at high temperature. The order of stress relaxation in terms of passivation layers is SiN/CoWB < SiN < SiCN < SiC, implying the order of mass transport at the interface. Using the kinetic model, the diffusivities and activation energies regarding passivation layers are calculated and reveal a good agreement with experimental results.

This paper presents a construction method regarding a tubular nano-mesh for which the anodic oxidation of aluminum (Al) wire is used. The first step of tubular-nano-mesh production is Al-wire anodization. A new anodizing device was made for the wire-based uniform anodization for this study, and a high-purity (99.999%) Al wire with a 2 mm diameter was used. Also, an electrolytic solution was used as a 0.07 M oxalic acid, while the electrolytic-solution temperature was maintained at -3℃. While the applied voltage and the process time were varied, the AAO (Anodic Aluminum Oxide) characteristics of the Al wire were observed. When 60 V was applied to the wire, alumina cracks were not evident, whereas the application of 100 V produced alumina cracks; this is because the growth rate of the nano-pore voltage affected the alumina shape. For the subsequent construction of the tubular alumina structure, an Al-etchant (HCl + H2O + CuCl2 + 2H2O) etched-Al portion of the anodized wire was employed. The final step is a pore-widening process that is implemented through the hole channel. The anodized wire was dipped in the alumina etchant, and the pore-wall removal was checked over time.