Journal article

Structural and optical properties of MgxAl1-xHy gradient thin films: a combinatorial approach

  • Gremaud, Robin Department of Physics and Astronomy, Condensed Matter Physics, Vrije Universiteit, Amsterdam, The Netherlands
  • Borgschulte, A. Department of Physics and Astronomy, Condensed Matter Physics, Vrije Universiteit, Amsterdam, The Netherlands
  • Chacon, C. Department of Physics, Uppsala University, Sweden
  • Mechelen, J. L. M. van Department of Physics and Astronomy, Condensed Matter Physics, Vrije Universiteit, Amsterdam, The Netherlands
  • Schreuders, H. Department of Physics and Astronomy, Condensed Matter Physics, Vrije Universiteit, Amsterdam, The Netherlands
  • Züttel, Andreas Institut de Physique, Université de Fribourg, Switzerland
  • Hjörvarsson, B. Department of Physics, Uppsala University, Sweden
  • Dam, B. Department of Physics and Astronomy, Condensed Matter Physics, Vrije Universiteit, Amsterdam, The Netherlands
  • Griessen, R. Department of Physics and Astronomy, Condensed Matter Physics, Vrije Universiteit, Amsterdam, The Netherlands
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    2006
Published in:
  • Applied Physics A. - 2006, vol. 84(1-2), no. 77-85
English The structural, optical and dc electrical properties of MgxAl1-x (0.2≤x≤0.9) gradient thin films covered with Pd/Mg are investigated before and after exposure to hydrogen. We use hydrogenography, a novel high-throughput optical technique, to map simultaneously all the hydride forming compositions and the kinetics thereof in the gradient thin film. Metallic Mg in the MgxAl1-x layer undergoes a metal-to-semiconductor transition and MgH₂ is formed for all Mg fractions x investigated. The presence of an amorphous Mg-Al phase in the thin film phase diagram enhances strongly the kinetics of hydrogenation. In the Al-rich part of the film, a complex H-induced segregation of MgH₂ and Al occurs. This uncommon large-scale segregation is evidenced by metal and hydrogen profiling using Rutherford backscattering spectrometry and resonant nuclear analysis based on the reaction ¹H(¹⁵N,αγ)¹²C. Besides MgH₂, an additional semiconducting phase is found by electrical conductivity measurements around an atomic [Al]/[Mg] ratio of 2 (x=0.33). This suggests that the film is partially transformed into Mg(AlH₄)₂ at around this composition.
Faculty
Faculté des sciences et de médecine
Department
Département de Physique
Language
  • English
Classification
Physics
License
License undefined
Identifiers
Persistent URL
https://folia.unifr.ch/unifr/documents/299964
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