Structural and vibrational properties of GaN

T. Deguchi, D. Ichiryu, K. Toshikawa, K. Sekiguchi, Takayuki Sota, R. Matsuo, T. Azuhata, M. Yamaguchi, T. Yagi, S. Chichibu, S. Nakamura

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    Abstract

    Structural and vibrational properties of device quality pure GaN substrate grown using a lateral epitaxial overgrowth (LEO) technique were studied using x-ray diffraction, Brillouin, Raman, and infrared spectroscopy. Lattice constants were found to be a = 3.1896±0.0002 Å and c = 5.1855 ±0.0002 Å. Comparing the results with those on GaN epilayer directly grown on sapphire substrate, it is shown that the GaN substrate is indeed of high quality, i.e., the lattice is relaxed. However the GaN substrate has a small enough but finite residual strain arising from the pileup of the lateral growth front on SiO2 masks in the course of LEO. It was also found that the elastic stiffness constants C13 and C44, are more sensitive to the residual strain than the optical phonon frequencies. The high frequency and static dielectric constants were found to be 5.14 and 9.04. The Born and Callen effective charges were found to be 2.56 and 0.50.

    Original languageEnglish
    Pages (from-to)1860-1866
    Number of pages7
    JournalJournal of Applied Physics
    Volume86
    Issue number4
    Publication statusPublished - 1999 Aug 15

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    ASJC Scopus subject areas

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

    Cite this

    Deguchi, T., Ichiryu, D., Toshikawa, K., Sekiguchi, K., Sota, T., Matsuo, R., Azuhata, T., Yamaguchi, M., Yagi, T., Chichibu, S., & Nakamura, S. (1999). Structural and vibrational properties of GaN. Journal of Applied Physics, 86(4), 1860-1866.