Dresden 2011 – scientific programme

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DS: Fachverband Dünne Schichten

DS 42: Poster I: Progress in Micro- and Nanopatterning: Techniques and Applications (jointly with O); Spins in Organic Materials; Ion Interactions with Nano Scale Materials; Organic Electronics and Photovoltaics; Plasmonics and Nanophotonics (jointly with HL and O); High-k and Low-k Dielectrics (jointly with DF); Organic Thin Films; Nanoengineered Thin Films; Layer Deposition Processes; Layer Properties: Electrical, Optical, and Mechanical Properties; Thin Film Characterisation: Structure Analysis and Composition; Application of Thin Films

DS 42.105: Poster

Wednesday, March 16, 2011, 15:00–17:30, P1

Optical switching properties and durability of a Mg-Fe alloy based thin film hydrogen sensor — •Marc K. Dietrich, Gunther Haas, André Portz, Andreas Laufer, Angelika Polity, and Bruno K. Meyer — I. Physikalisches Institut, Giessen, Germany

Mg-Fe alloy based hydrogen gas sensors were produced by a RF sputtering process. By exposure to a hydrogen containing gas mixture the Mg-metal alloy switches from the metal phase into a hydride phase, thereby the optical reflection shows a change. A Pd top layer acts as hydrogen catalyst. The degradation of the hydrogenation speed (sensor reaction) and the switching durability are well known problems of such Mg-metal based switching mirrors. Furthermore, there is a delay of sensor reaction after some weeks of storage (in air).

In order to solve these problems, we added a Ti buffer layer between MgFe and Pd layer. The buffer layer inserted sensor system featured an improvement of sensor reaction and switching durability. A polytetrafluoroethylene (PTFE) covering coat was added and reduced the sensor degeneration after the storage. Furthermore, there was an additional improvement of switching durability. Samples of PTFE/Pd/Ti/MgFe achieved over 1000 switching cycles (with 4 % hydrogen in air) without a significant performance reduction.