Structural defects in heteroepitaxial and homoepitaxial GaN

Zuzanna Liliental-Weber, S. Ruvimov, Ch Kisielowski, Y. Chen, W. Swider, J. Washburn, Nathan Newman, A. Gassmann, X. Liu, L. Schloss, E. R. Weber, I. Grzegory, M. Bockowski, J. Jun, T. Suski, al et al

Research output: Chapter in Book/Report/Conference proceedingConference contribution

43 Scopus citations


The microstructure and characteristic defects of heteroepitaxial GaN films grown on sapphire using molecular beam epitaxy (MBE) and metal-organic-chemical-vapor-deposition (MOCVD) methods and of homoepitaxial GaN grown on bulk substrates are described based on transmission electron microscopy (TEM), x-ray diffraction, and cathodoluminescence (CL) studies. The difference in arrangement of dislocations along grain boundaries and the influence of buffer layers on the quality of epitaxial films is described. The structural quality of GaN epilayers is compared to that of bulk GaN crystals grown from dilute solution of atomic nitrogen in liquid gallium. The full width at half maximum (FWHM) of the x-ray rocking curves for these crystals was in the range of 20-30 arc sec, whereas for the heteroepitaxially grown GaN the FWHM was in the range of 5-20 arc min. Homoepitaxial MBE grown films had FWHMs of about 40 arc sec. The best film quality was obtained for homoepitaxial films grown using MOCVD; these samples were almost free from extended defects. For the bulk GaN crystals a substantial difference in crystal perfection was observed for the opposite sides of the plates shaped normal to the c direction. On one side the surface was almost atomically flat, and the underlying material was free of any extended structural defects, while the other side was rough, with a high density of planar defects. This difference was related to the polarity of the crystal. A large difference in crystal stoichiometry was also observed within different sublayers of the crystals. Based on convergent beam electron diffraction and cathodoluminescence, it is proposed that Ga N antisite defects are related to the yellow luminescence observed in these crystals.

Original languageEnglish (US)
Title of host publicationMaterials Research Society Symposium - Proceedings
PublisherMaterials Research Society
Number of pages12
StatePublished - 1996
Externally publishedYes
EventProceedings of the 1995 MRS Fall Meeting - Boston, MA, USA
Duration: Nov 26 1995Dec 1 1995


OtherProceedings of the 1995 MRS Fall Meeting
CityBoston, MA, USA

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials


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