Regensburg 2010 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 26: Poster Session

MM 26.50: Poster

Dienstag, 23. März 2010, 14:45–16:30, Poster C

Properties and stability of hydrogen sensors based on magnesium-iron thin films — •Gunther Haas, Jennifer Stiebich, Andreas Laufer, Marc Dietrich, Angelika Polity, and Bruno K. Meyer — I. Physikalisches Institut, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany

Thin magnesium-iron films, capped by a catalytic Pd layer, were prepared by RF diode sputtering. Upon exposure to hydrogen the films show reversible changes in the optical reflection and electrical resistivity. These switching effects can be use to detect hydrogen gas. We investigated the influence of the sputter parameters and the layer thickness on the sensor performance in air and argon atmosphere. Due to the layer optimisation the sensitivity could be extended from 4% to less than 1000 ppm hydrogen in air and response times faster then 10 s were obtained. Considering the stability and durability of the sensors, the long-term stability is restricted by the interdiffusion of Mg into the Pd layer and fractional oxidation. Therefore we investigated the effect of an additional metal layer which allows hydrogen diffusion but suppresses the oxidation and/or the interdiffusion of Mg.