Atomic structures of supersaturated ZnO- Al2 O3 solid solutions

Satoru Yoshioka, Fumiyasu Oba, Rong Huang, Isao Tanaka, Teruyasu Mizoguchi, Tomoyuki Yamamoto

    Research output: Contribution to journalArticle

    56 Citations (Scopus)

    Abstract

    Supersaturated ZnO- Al2 O3 (>20 at. % Al) thin films are grown by pulsed laser deposition technique on silica glass substrates at 600 °C. They are characterized by combining x-ray diffraction, Al-K edge x-ray absorption near edge structures (XANESs), high resolution transmission electron microscope (TEM) imaging, TEM analysis, and a series of first principles calculations. The films are composed of textured wurtzite grains with c planes parallel to the substrate. The distance between c planes expands significantly when the Al concentration is greater than 10 at. %. The expansion disappears after annealing the films at above 800 °C. High density of dislocationlike defects is found in the as deposited film. Any segregation of Al cannot be detected either at the grain boundaries or inside the grains. The lattice expansion toward c axis and the experimental XANES can be satisfactorily explained by taking a hypothetical homologous model with the composition of (ZnO)3 (Al2 O3) as the local environment of Al in the supersaturated solid solution. Simplified substitutional models with Al at the Zn site in wurtzite ZnO cannot explain these experimental results. First principles calculations show that the homologous phase is energetically more favorable than the simplified substitutional models, although decomposition into ZnO and Zn Al2 O4 is more favorable than the homologous phase. The local atomic structures of the supersaturated solid solution are therefore concluded to be analogous to the metastable homologous phase.

    Original languageEnglish
    Article number014309
    JournalJournal of Applied Physics
    Volume103
    Issue number1
    DOIs
    Publication statusPublished - 2008

    Fingerprint

    atomic structure
    solid solutions
    x ray absorption
    wurtzite
    electron microscopes
    expansion
    silica glass
    pulsed laser deposition
    x ray diffraction
    grain boundaries
    decomposition
    annealing
    high resolution
    defects
    thin films

    ASJC Scopus subject areas

    • Physics and Astronomy (miscellaneous)
    • Physics and Astronomy(all)

    Cite this

    Atomic structures of supersaturated ZnO- Al2 O3 solid solutions. / Yoshioka, Satoru; Oba, Fumiyasu; Huang, Rong; Tanaka, Isao; Mizoguchi, Teruyasu; Yamamoto, Tomoyuki.

    In: Journal of Applied Physics, Vol. 103, No. 1, 014309, 2008.

    Research output: Contribution to journalArticle

    Yoshioka, S, Oba, F, Huang, R, Tanaka, I, Mizoguchi, T & Yamamoto, T 2008, 'Atomic structures of supersaturated ZnO- Al2 O3 solid solutions', Journal of Applied Physics, vol. 103, no. 1, 014309. https://doi.org/10.1063/1.2829785
    Yoshioka, Satoru ; Oba, Fumiyasu ; Huang, Rong ; Tanaka, Isao ; Mizoguchi, Teruyasu ; Yamamoto, Tomoyuki. / Atomic structures of supersaturated ZnO- Al2 O3 solid solutions. In: Journal of Applied Physics. 2008 ; Vol. 103, No. 1.
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