Reduced defect densities in cubic GaN epilayers with AlGaN/GaN superlattice underlayers grown on (001) GaAs substrates by Metalorganic vapor phase epitaxy

Mutsumi Sugiyama, Taiki Nosaka, Tomonori Suzuki, Takashi Koida, Kiyomi Nakajima, Toyomi Aoyama, Masatomo Sumiya, Toyohiro Chikyow, Akira Uedono, Shigefusa F. Chichibu

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

The effects of AlxGa1-xN/GaN superlattice (SL) insertion on the structural homogeneity, photoluminescence (PL) lifetime (τPL), 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 significantly decreased by the insertion of appropriate short-period AlGaN/GaN SLs 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 (VGa)-related defects in the c-GaN epilayer was significantly reduced. Simultaneously, the value of excitonic PL lifetime at 293 K was improved from approximately 20 ps to 230 ps, indicating a tremendous reduction of the nonradiative defect density.

Original languageEnglish
Pages (from-to)958-965
Number of pages8
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume43
Issue number3
DOIs
Publication statusPublished - 2004 Mar
Externally publishedYes

Keywords

  • Cubic GaN
  • GaAs substrate
  • Metalorganic vapor phase epitaxy (MOVPE)
  • Positron annihilation technique
  • Superlattice (SL)

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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