1. Vacancy defects in O-doped GaN grown by molecular-beam epitaxy: The role of growth polarity and stoichiometry.
- Author
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Rummukainen, M., Olla, J., Laakso, A., Saarinen, K., Ptak, A. J., and Myers, T. H.
- Subjects
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MOLECULAR beam epitaxy , *EPITAXY , *STOICHIOMETRY , *PHYSICAL & theoretical chemistry , *POSITRON annihilation , *ELECTRONS - Abstract
Positron annihilation spectroscopy is used to study vacancy defects in GaN grown by molecular-beam epitaxy due to different polar directions and varying stoichiometry conditions during oxygen doping. We show that Ga-polar material is free of compensating Ga vacancies up to [O]=1018 cm-3 in Ga stable growth, but high concentrations of VGa are formed in N-stable conditions. We also show that vacancy clusters are formed in N-polar material grown in Ga stable conditions, which may be related to the higher reactivity of the N-polar surface. These clusters have no apparent influence on the electrical properties of the material. We thus infer that their charge state is neutral. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]
- Published
- 2004
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