Dislocations at the interface between sapphire and GaN

Research output: Contribution to journalArticle


  • Aapo Lankinen
  • T. Lang
  • Sami Suihkonen

  • O. Svensk
  • A. Säynätjoki
  • T. O. Tuomi
  • P. J. McNally
  • M. Odnoblyudov
  • V. Bougrov
  • A. N. Danilewsky
  • P. Bergman
  • R. Simon

Research units

  • Dept. of Micro- and Nanosciences/SMARAD2
  • Dublin City University
  • Ioffe Institute
  • Albert-Ludwigs-Universität
  • Linköping University
  • ANKA


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

ID: 4220892