Development of palladium-based hydrogen thin film sensor using silicon oxide substrate

In this research, the fabrication and testing of three types of thin films are investigated for the study of hydrogen sensors. Individual thin films of pure palladium (Pd) and two alloys of Pd-silver and Pd-yttrium (Y) are fabricated on silicon oxide substrates using a vacuum evaporation technique. In this process, the surface area and the thickness are kept constant for all the fabricated thin films. The electrical resistance and sensing properties of the structures in conjunction with 5 % hydrogen concentration at room temperature are obtained from the resistance-time and sensor response-time characteristics respectively and the results are compared and discussed. The thin film made with Pd-Y alloy shows the best sensor response and reversibility with time to hydrogen. These results show that the Pd-Y thin film can be further improved for application in high performance hydrogen sensors at room temperature. Suggestions are also made as to how to modify and improve the fabricated thin film sensor further.