Narrow Results

In this study, two hydrogen sensors with Pd/SiO₂/Si and Ni/SiO₂/Si structures have been fabricated. Palladium nanoparticles are synthesized and then deposited on the oxide surface using spin coating. Capacitance–voltage curves for the Pd/SiO₂/Si sensor at room temperature and for the Ni/SiO₂/Si sensor at 140${}^{\circ }$C in pure nitrogen and 1% H₂–N₂ mixture are described. The time required for reaching 90% of the steady-state signal magnitude ($t_{90\%}$) for Pd/SiO₂/Si capacitor was 1.4s and for Ni/SiO₂/Si capacitor was 90 s. The time interval for recovery from 90% to 10% of steady-state signal magnitude ($t_{10\%})$ for Pd/SiO₂/Si capacitor was 14s and for Ni/SiO₂/Si capacitor was 40min. For the Pd/SiO₂/Si capacitor, the response is 88% and for Ni/SiO₂/Si capacitor the response is 29%. Comparison of Pd nanoparticles capacitive- and resistance-based sensors shows that the metal-oxide-semiconductor capacitive is faster and more sensitive than the resistance-based hydrogen gas sensors.