Influence of dopants and substrate material on the formation of Ga vacancies in epitaxial GaN layers

J. Oila, V. Ranki, J. Kivioja, K. Saarinen, Pekka Hautojärvi, Jari Likonen, J. Baranowski, T. Pakula, T. Suski, M. Leszcynski, I. Grzegory

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Abstract

We have applied a low-energy positron beam and secondary ion mass spectrometry to study defects in homoepitaxial and heteroepitaxial GaN layers. Positron experiments reveal high concentrations of Ga vacancies in nominally undoped n-type GaN, where the conductivity is due to unintentional oxygen incorporation. Ga vacancies are observed in both homoepitaxial and heteroepitaxial layers, indicating that their formation is independent of the dislocation density. No Ga vacancies are detected in p-type or semi-insulating samples doped with Mg, as predicted by the theoretical formation energies. In samples where n-type conductivity is due to Si doping and the incorporation of oxygen impurities is suppressed, the concentration of Ga vacancies is much lower than in n-type samples containing oxygen. This indicates that the presence of oxygen donor in GaN promotes the formation of Ga vacancy. We suggest that this effect is due to the creation of VGa−ON complexes during the epitaxial growth.
Original languageEnglish
Article number045205
Number of pages8
JournalPhysical Review B: Condensed Matter and Materials Physics
Volume63
Issue number4
DOIs
Publication statusPublished - 2001
MoE publication typeA1 Journal article-refereed

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Epitaxial layers
Vacancies
Doping (additives)
Oxygen
Substrates
Positrons
oxygen
positrons
conductivity
energy of formation
Secondary ion mass spectrometry
Dislocations (crystals)
Epitaxial growth
secondary ion mass spectrometry
Impurities
impurities
Defects
defects
Experiments
energy

Cite this

Oila, J. ; Ranki, V. ; Kivioja, J. ; Saarinen, K. ; Hautojärvi, Pekka ; Likonen, Jari ; Baranowski, J. ; Pakula, T. ; Suski, T. ; Leszcynski, M. ; Grzegory, I. / Influence of dopants and substrate material on the formation of Ga vacancies in epitaxial GaN layers. In: Physical Review B: Condensed Matter and Materials Physics. 2001 ; Vol. 63, No. 4.
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abstract = "We have applied a low-energy positron beam and secondary ion mass spectrometry to study defects in homoepitaxial and heteroepitaxial GaN layers. Positron experiments reveal high concentrations of Ga vacancies in nominally undoped n-type GaN, where the conductivity is due to unintentional oxygen incorporation. Ga vacancies are observed in both homoepitaxial and heteroepitaxial layers, indicating that their formation is independent of the dislocation density. No Ga vacancies are detected in p-type or semi-insulating samples doped with Mg, as predicted by the theoretical formation energies. In samples where n-type conductivity is due to Si doping and the incorporation of oxygen impurities is suppressed, the concentration of Ga vacancies is much lower than in n-type samples containing oxygen. This indicates that the presence of oxygen donor in GaN promotes the formation of Ga vacancy. We suggest that this effect is due to the creation of VGa−ON complexes during the epitaxial growth.",
author = "J. Oila and V. Ranki and J. Kivioja and K. Saarinen and Pekka Hautoj{\"a}rvi and Jari Likonen and J. Baranowski and T. Pakula and T. Suski and M. Leszcynski and I. Grzegory",
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Oila, J, Ranki, V, Kivioja, J, Saarinen, K, Hautojärvi, P, Likonen, J, Baranowski, J, Pakula, T, Suski, T, Leszcynski, M & Grzegory, I 2001, 'Influence of dopants and substrate material on the formation of Ga vacancies in epitaxial GaN layers', Physical Review B: Condensed Matter and Materials Physics, vol. 63, no. 4, 045205. https://doi.org/10.1103/PhysRevB.63.045205

Influence of dopants and substrate material on the formation of Ga vacancies in epitaxial GaN layers. / Oila, J.; Ranki, V.; Kivioja, J.; Saarinen, K.; Hautojärvi, Pekka; Likonen, Jari; Baranowski, J.; Pakula, T.; Suski, T.; Leszcynski, M.; Grzegory, I.

In: Physical Review B: Condensed Matter and Materials Physics, Vol. 63, No. 4, 045205, 2001.

Research output: Contribution to journalArticleScientificpeer-review

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T1 - Influence of dopants and substrate material on the formation of Ga vacancies in epitaxial GaN layers

AU - Oila, J.

AU - Ranki, V.

AU - Kivioja, J.

AU - Saarinen, K.

AU - Hautojärvi, Pekka

AU - Likonen, Jari

AU - Baranowski, J.

AU - Pakula, T.

AU - Suski, T.

AU - Leszcynski, M.

AU - Grzegory, I.

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PY - 2001

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AB - We have applied a low-energy positron beam and secondary ion mass spectrometry to study defects in homoepitaxial and heteroepitaxial GaN layers. Positron experiments reveal high concentrations of Ga vacancies in nominally undoped n-type GaN, where the conductivity is due to unintentional oxygen incorporation. Ga vacancies are observed in both homoepitaxial and heteroepitaxial layers, indicating that their formation is independent of the dislocation density. No Ga vacancies are detected in p-type or semi-insulating samples doped with Mg, as predicted by the theoretical formation energies. In samples where n-type conductivity is due to Si doping and the incorporation of oxygen impurities is suppressed, the concentration of Ga vacancies is much lower than in n-type samples containing oxygen. This indicates that the presence of oxygen donor in GaN promotes the formation of Ga vacancy. We suggest that this effect is due to the creation of VGa−ON complexes during the epitaxial growth.

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SN - 2469-9950

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