Regensburg 2007 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 17: Hydrogen in materials

MM 17.1: Talk

Tuesday, March 27, 2007, 10:15–10:30, H6

Hydrogen absorption in epitaxial Nb-films: a STM-study — •Kai Nörthemann and Astrid Pundt — Institut für Materialphysik, Universität Göttingen, Friedrich-Hund-Platz 1, 37077 Göttingen

The hydrogen absorption and hydride formation in thin epitaxial films is presented in this contribution, using the model system Niobium-Hydrogen.

With the surface sensitive scanning tunneling microscopy (STM) it is possible to study the hydrogen uptake inside a film because of its strong out-of-plane expansion. Since this is proportional to the H-concentration this effect can, especially, be used to study the hydride evolution. It will be shown that the surface topography tells about the hydride shape and microstructure inside the film. Two different types of hydride-related surface topographies were found: smooth hills (early stages) and rough surface pattern (later stages). The shape of the related hydrides were determined with the help of finite-element analysis. The origin of the two different surface topographies will be presented.

This work is financially supported by the DFG via SFB 602.