Nano-Crystalline Palladium-Film Catalysts Deposited By E-beam Evaporation Aiming Hydrogen Sensing

Abstract

Palladium thin films were deposited on previously oxidized silicon wafers using E-beam evaporation aiming hydrogen sensing. The hydrogen incorporation after different kinds of annealings was studied. The changes in the film characteristics during hydrogen incorporation at different temperatures were evaluated using Atomic Force Microscopy (AFM), X-Ray Difraction (XRD) techniques, Energy Dispersion System together a MEV microscope (EDS) and Rutherford Backscattering Spectrometry (RBS). The hydrogen incorporation into the palladium lattice under atmospheric pressure showed to be predominantly in α phase for temperature ranging from 70oC to 110oC (for two different hydrogen concentrations: air and FG expositions). The electrical sheet resistance characterizations were sensitive to hydrogen incorporation, presenting quantitative values. Also, palladium films presented a nano-crystalline structure suitable for hydrogen sensing at temperatures lower than 100oC.