Reduction of point defect density in cubic GaN epilayers on (001) GaAs substrates using AlxGa1-xN/GaN superlattice underlayers

S. F. Chichibu, M. Sugiyama, T. Nozaka, T. Suzuki, T. Onuma, K. Nakajima, T. Aoyama, M. Sumiya, T. Chikyow, A. Uedono

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5 Citations (Scopus)


Effects of AlxGa1-xN/GaN superlattice (SL) insertion on the structural homogeneity, photoluminescence (PL) lifetime, and defect densities were studied in cubic (c-) GaN epilayers on (001) GaAs substrates grown by low-pressure metalorganic vapor-phase epitaxy. Values of the full-width at half-maximum (FWHM) of both the (002) X-ray diffraction peak and near-band-edge excitonic PL peak were decreased by a factor of 2, and the room-temperature PL intensity was improved by a factor greater than 10 through the use of double 15-period 3,8-nm-thick Al0.35Ga0.65N/2. 5-nm-thick GaN SL layers between the c-GaN epilayer and the c-GaN template layer prepared on a substrate-decomposition-shielding GaN layer deposited at a low temperature. The density or size of Ga-vacancy (V Ga)-related defects in the c-GaN epilayer was also significantly reduced, and simultaneous increase in the excitonic PL lifetime at 293 K from approximately 20 ps to 230 ps indicated a tremendous reduction of the nonradiative defect density.

Original languageEnglish
Pages (from-to)481-488
Number of pages8
JournalJournal of Crystal Growth
Issue number1-4 SPEC. ISS.
Publication statusPublished - 2004 Dec 10
Externally publishedYes


  • A1. Positron annihilation
  • A3. Metalorganic vapor phase epitaxy (MOVPE)
  • A3. Superlattice (SL)
  • B1. I GaAs substrate
  • B1. Nitrides
  • Bl. Cubic GaN

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry

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