Study of thin films polarity of group III nitrides

K. Dovidenko*, S. Oktyabrsky, J. Narayan, M. Razeghi

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review


Thin films of GaN grown by MOCVD on (0001) sapphire were studied by transmission electron microscopy in order to correlate the observed extended defects with crystal polarity of the films. We propose relatively simple and unambiguous method of polarity determination for wurtzite group III nitrides based on the dependence of the intensity of diffracted beams upon thickness of the specimen. Due to the dynamic scattering by polar structure, the convergent beam electron diffraction patterns lose inversion symmetry and become in fact fingerprints of the structure carrying information about crystal polarity. In this study, we have used the thinnest regions of the specimens (< 15 nm) and multiple diffraction spots in high-symmetry orientation for polarity determination. The films were found to have Ga-polar surfaces, either being unipolar, or containing thin (10-30 nm in diameter) columnar inversion domains (IDs) of N-polarity. The occurrence of IDs was correlated with specific types of dislocation distribution in the films.

Original languageEnglish (US)
Pages (from-to)G6.46
JournalMaterials Research Society Symposium - Proceedings
StatePublished - Dec 1 1999
EventProceedings of the 1998 MRS Fall Meeting - Symposium on 'GaN and Related Alloys' - Boston, MA, USA
Duration: Nov 30 1998Dec 4 1998

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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