Platinum-Nickel alloy thin films for low concentration hydrogen sensor application

Hydrogen (H-2) gas sensing properties of platinum (Pt) -nickel (Ni) alloy thin films deposited on a glass substrate by sputter technique are investigated depending on alloy composition, temperature and H-2 concentration. The structural properties of Pt-Ni alloy thin films are characterized by XRD, SEM and EDS techniques. The amount of Ni atom in the alloy thin films is increased from 0% up to 60% and the H-2 sensing properties of the alloy thin film sensors are examined in the concentration range of 25-1000 ppm H-2. The results revealed that the H-2 sensing mechanism of the same thickness pure Pt and Pt-Ni alloy thin films could be explained with surface scattering phenomenon, and the Pt-79-Ni-21 alloy thin film exhibited the best sensing performance to H-2 at all measured temperature ranges. The limit of detection for Pt and Pt-Ni alloy thin films is calculated as lower than 1 ppm, and the response times of the films are decreased with rising H-2 concentration and temperature. (C) 2021 Elsevier B.V. All rights reserved.