Regensburg 2007 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 17: Hydrogen in materials

MM 17.4: Talk

Tuesday, March 27, 2007, 11:00–11:15, H6

Hydrogen sensors based on magnesium-x (x = Al, Ti, Fe, V and Zn) thin films — •Andreas Laufer, Baker Farangis, Jennifer Stiebich, and Bruno K. Meyer — I. Physikalisches Institut, Justus-Liebig-Universität Giessen, Heinrich-Buff-Ring 16, 35392 Giessen, Germany

We investigated hydrogen sensors based on magnesium-x (x = Al, Ti, Fe, V and Zn) thin films with a palladium over-layer operating at room temperature. These thin films prepared by RF-sputter-deposition show a very large change in both reflectance and transmittance during the absorption of hydrogen gas. The decrease in reflectance during hydrogenation was studied by using a GaAs infrared emitter and silicon NPN phototransistor as light source and detector. The change of optical properties is believed to result from reversible formation of MgH_x (x ≤ 2). The reflectance decrease is proportional to the hydrogen concentration (0.1-4% H₂ in Argon). The response time (0-90% of signal) is under 10 seconds depending on the composition of the Mg-alloy.