Photoluminescence and positron annihilation studies on Mg-doped nitrogen-polarity semipolar (10̄1̄1) GaN heteroepitaxial layers grown by metalorganic vapor phase epitaxy

T. Onuma, A. Uedono, H. Asamizu, H. Sato, J. F. Kaeding, M. Iza, S. P. Denbaars, S. Nakamura, S. F. Chichibu

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11 Citations (Scopus)

Abstract

The influences of enhanced stacking fault (SF) formation, which is peculiar to nitrogen-(N-) polarity growth and lattice-mismatched semipolar heteroepitaxy, on the electrical properties of (10̄1̄1) Mg-doped GaN (GaN:Mg) epilayers were investigated. Although the residual donor concentration was higher than (0001) GaN because of N-polar growth, comparatively low Mg doping (3× 1019 cm-3) gave a hole concentration approximately 1.5× 1018 cm-3, which was an order of magnitude higher than (0001) GaN:Mg. As the acceptor ionization energy estimated from low temperature photoluminescence was quite similar for (10̄1̄1) and (0001) GaN:Mg, the high Mg activation seems to result with the aid of high density SFs. Because the Doppler broadening S parameter for the positron annihilation measurement, which reflects the concentration or size of negatively charged cation vacancies, of (10̄1̄1) GaN:Mg was smaller than (0001) case, (10̄1̄1) orientation is well suited to Mg-doping.

Original languageEnglish
Article number091913
JournalApplied Physics Letters
Volume96
Issue number9
DOIs
Publication statusPublished - 2010

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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