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

Hydrogen (H2) 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 H2 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 H2 sensing properties of the alloy thin film sensors are examined in the concentration range of 25–1000 ppm H2. The results revealed that the H2 sensing mechanism of the same thickness pure Pt and Pt-Ni alloy thin films could be explained with surface scattering phenomenon, and the Pt79-Ni21 alloy thin film exhibited the best sensing performance to H2 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 H2 concentration and temperature.