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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    title = "Influence of dopants and substrate material on the formation of Ga vacancies in epitaxial GaN layers",
    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

    TY - JOUR

    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.

    N1 - Project code: K9SU00369

    PY - 2001

    Y1 - 2001

    N2 - 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.

    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.

    U2 - 10.1103/PhysRevB.63.045205

    DO - 10.1103/PhysRevB.63.045205

    M3 - Article

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    JO - Physical Review B

    JF - Physical Review B

    SN - 2469-9950

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