Comparison of Fast Response and Recovery Pd Nanoparticles and Ni Thin Film Hydrogen Gas Sensors Based on Metal-Oxide-Semiconductor Structure

Abstract

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[Formula: see text]C in pure nitrogen and 1% H2–N2 mixture are described. The time required for reaching 90% of the steady-state signal magnitude ([Formula: see text]) for Pd/SiO2/Si capacitor was 1.4[Formula: see text]s and for Ni/SiO2/Si capacitor was 90 s. The time interval for recovery from 90% to 10% of steady-state signal magnitude ([Formula: see text] for Pd/SiO2/Si capacitor was 14[Formula: see text]s and for Ni/SiO2/Si capacitor was 40[Formula: see text]min. 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.