Vacancy-type defects in Mg-doped GaN grown by ammonia-based molecular beam epitaxy probed using a monoenergetic positron beam

Journal Article · Tue Jun 28 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4954288· OSTI ID:22596832

Uedono, Akira ^[1]; Malinverni, Marco; Martin, Denis; Grandjean, Nicolas ^[2]; Okumura, Hironori ^[1]; Ishibashi, Shoji ^[3]

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1. Division of Applied Physics, Faculty of Pure and Applied Science, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan)
2. Institute of Physics, Ecole Polytechnique Fédérale de Lausanne, CH-1015 Lausanne (Switzerland)
3. Research Center for Computational Design of Advanced Functional Materials (CD-FMat), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan)

Vacancy-type defects in Mg-doped GaN were probed using a monoenergetic positron beam. GaN films with a thickness of 0.5–0.7 μm were grown on GaN/sapphire templates using ammonia-based molecular beam epitaxy and characterized by measuring Doppler broadening spectra. Although no vacancies were detected in samples with a Mg concentration [Mg] below 7 × 10{sup 19 }cm{sup −3}, vacancy-type defects were introduced starting at above [Mg] = 1 × 10{sup 20 }cm{sup −3}. The major defect species was identified as a complex between Ga vacancy (V{sub Ga}) and multiple nitrogen vacancies (V{sub N}s). The introduction of vacancy complexes was found to correlate with a decrease in the net acceptor concentration, suggesting that the defect introduction is closely related to the carrier compensation. We also investigated Mg-doped GaN layers grown using In as the surfactant. The formation of vacancy complexes was suppressed in the subsurface region (≤80 nm). The observed depth distribution of defects was attributed to the thermal instability of the defects, which resulted in the introduction of vacancy complexes during the deposition process.

• OSTI ID: 22596832
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 24; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
AMMONIA
DEFECTS
DEPTH
DOPED MATERIALS
DOPPLER BROADENING
GALLIUM NITRIDES
LAYERS
MAGNESIUM
MOLECULAR BEAM EPITAXY
MOLECULAR BEAMS
NITROGEN
POSITRON BEAMS
POSITRONS
SAPPHIRE
SPATIAL DISTRIBUTION
SPECTRA
THICKNESS
VACANCIES