Dislocations at the interface between sapphire and GaN

Aapo Lankinen*, T. Lang, S. Suihkonen, O. Svensk, A. Säynätjoki, T. O. Tuomi, P. J. McNally, M. Odnoblyudov, V. Bougrov, A. N. Danilewsky, P. Bergman, R. Simon

*Corresponding author for this work

    Research output: Contribution to journalArticleScientificpeer-review

    2 Citations (Scopus)


    GaN layers grown by metal organic vapour phase epitaxy on sapphire were imaged by synchrotron radiation X-ray topography. The threading dislocations could not be resolved in the topographs due to their high density, but a smaller density of about 10 5 cm -2 defects were seen in the interface between GaN and sapphire by utilizing large-area back-reflection topography for the sapphire substrates. The misfit dislocation images in the topographs form a well-resolved cellular network, in which the average cell size is roughly 30 μm. Different cell shapes in the misfit dislocation networks are observed on different samples. Also, images of small-angle grains of similar size were found in transmission section topographs of the GaN layers.

    Original languageEnglish
    Pages (from-to)143-148
    Number of pages6
    JournalJournal of Materials Science: Materials in Electronics
    Issue number2
    Publication statusPublished - Feb 2008
    MoE publication typeA1 Journal article-refereed

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