Applied Physics A

, Volume 84, Issue 1, pp 77–85

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

  • R. Gremaud
  • A. Borgschulte
  • C. Chacon
  • J.L.M. van Mechelen
  • H. Schreuders
  • A. Züttel
  • B. Hjörvarsson
  • B. Dam
  • R. Griessen
Article

DOI: 10.1007/s00339-006-3579-z

Cite this article as:
Gremaud, R., Borgschulte, A., Chacon, C. et al. Appl. Phys. A (2006) 84: 77. doi:10.1007/s00339-006-3579-z

Abstract

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.

Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  • R. Gremaud
    • 1
  • A. Borgschulte
    • 1
  • C. Chacon
    • 2
  • J.L.M. van Mechelen
    • 1
  • H. Schreuders
    • 1
  • A. Züttel
    • 3
  • B. Hjörvarsson
    • 2
  • B. Dam
    • 1
  • R. Griessen
    • 1
  1. 1.Department of Physics and Astronomy, Condensed Matter PhysicsVrije UniversiteitAmsterdamThe Netherlands
  2. 2.Department of PhysicsUppsala UniversityUppsalaSweden
  3. 3.Institut de PhysiqueUniversité de FribourgFribourgSwitzerland

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