Palladium–silver thin film for hydrogen sensing

In this paper, a palladium–silver (Pd–Ag) thin film was fabricated and studied for hydrogen gas sensing. A zigzag-shaped microstructure of Pd–Ag was coated on a porous alumina substrate through a combination of microfabrication techniques including photolithography, thin film sputtering and electron beam vacuum evaporation. The atomic ratio of the two metals is controlled at Pd:Ag = 3:2. To evaluate the H2 sensitivity of the fabricated device, the electrical resistance of the film was measured toward hydrogen concentration change. Experimental results show that the sensing element fabricated this way demonstrates high sensitivity, fast response and excellent reversibility to hydrogen gas. The sensing performance of the mixed metal film is much better than that of the palladium film. The present sensor is promising for room temperature hydrogen leakage detection and related applications.