Correlation between the violet luminescence intensity and defect density in AlN epilayers grown by ammonia-source molecular beam epitaxy

Takuya Hoshi, Takahiro Koyama, Mariko Sugawara, Akira Uedono, John F. Kaeding, Rajat Sharma, Shuji Nakamura, Shigefusa F. Chichibu

Research output: Contribution to journalConference articlepeer-review

8 Citations (Scopus)

Abstract

Intensity ratios of deep cathodoluminescence (CL) bands at 4.6, 3.8 and 3.1 eV to the near-band-edge emission of AlN epilayers grown by NH 3-source molecular beam epitaxy were correlated with the change in S parameter of positron annihilation measurement, which represents the concentration or size of Al vacancies (VAl). The origins of the deep emission bands were assigned to donor-acceptor pairs associated with V Al and/or VAl-defect complexes. The VAl concentration was decreased by adjusting the flux ratio of NH3 to Al and growth temperature, resulting in observation of fine excitonic features in the CL spectra. From the energy separation between the ground and first excited states, the binding energy of free A-exciton was estimated to be 48 meV.

Original languageEnglish
Pages (from-to)2129-2132
Number of pages4
JournalPhysica Status Solidi (C) Current Topics in Solid State Physics
Volume5
Issue number6
DOIs
Publication statusPublished - 2008
Event7th International Conference of Nitride Semiconductors, ICNS-7 - Las Vegas, NV, United States
Duration: 2007 Sep 162007 Sep 21

ASJC Scopus subject areas

  • Condensed Matter Physics

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