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Impurity decoration of native vacancies in Ga and N sublattices of gallium nitride

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dc.contributor Aalto-yliopisto fi
dc.contributor Aalto University en
dc.contributor.author Hautakangas, Sami
dc.date.accessioned 2012-02-17T06:59:41Z
dc.date.available 2012-02-17T06:59:41Z
dc.date.issued 2005-05-20
dc.identifier.isbn 951-22-7667-4
dc.identifier.issn 1455-1802
dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/2567
dc.description.abstract The effects of impurity atoms as well as various growth methods to the formation of vacancy type defects in gallium nitride (GaN) have been studied by positron annihilation spectroscopy. It is shown that vacancy defects are formed in Ga or N sublattices depending on the doping of the material. Vacancies are decorated with impurity atoms leading to the compensation of the free carriers of the samples. In addition, the vacancy clusters are found to be present in significant concentrations in n-type as well as in p-type GaN. Nitrogen vacancies compensate Mg impurities in magnesium doped GaN. The high Mg content creates a defect profile with a low vacancy concentration near the surface. Post-growth annealing dissociates Vn-related complexes activating the p-type conductivity. Also the vacancy profile is made homogeneous by thermal treatment in highly Mg-doped GaN. The direct experimental evidence of oxygen decorated Ga vacancy is obtained in O-doped n-type GaN. The present study shows that VGa-ON is distinguishable from an isolated Ga vacancy by positron annihilation spectroscopy. Yellow luminescence (YL) is common in n-type GaN, which is usually related to Ga vacancy defects. However, carbon doped semi-insulating GaN is exhibiting strong YL emission, but without the presence of Ga vacancies. The YL is attributed to C interstitials. The investigations concerning silicon doped GaN and GaN grown by the mass-transport method reveal vacancy type defects, which were identified as vacancy clusters. en
dc.format.extent 38, [35]
dc.format.mimetype application/pdf
dc.language.iso en en
dc.publisher Helsinki University of Technology en
dc.publisher Teknillinen korkeakoulu fi
dc.relation.ispartofseries Dissertations of Laboratory of Physics, Helsinki University of Technology en
dc.relation.ispartofseries 132 en
dc.relation.haspart S. Hautakangas, J. Oila, M. Alatalo, K. Saarinen, L. Liszkay, D. Seghier, and H. P. Gislason. 2003. Vacancy defects as compensating centers in Mg-doped GaN. Physical Review Letters 90, 137402. [article1.pdf] © 2003 American Physical Society. By permission.
dc.relation.haspart S. Hautakangas, K. Saarinen, L. Liszkay, J. A. Freitas, and R. L. Henry. The role of open volume defects in Mg-doped GaN studied by positron annihilation spectroscopy. Physical Review B, submitted for publication. [article2.pdf] © 2005 by authors and © 2005 American Physical Society. By permission.
dc.relation.haspart P. Laukkanen, S. Lehkonen, P. Uusimaa, M. Pessa, J. Oila, S. Hautakangas, K. Saarinen, J. Likonen, and J. Keränen. 2002. Structural, electrical, and optical properties of defects in Si-doped GaN grown by molecular-beam epitaxy on hydride vapor phase epitaxy GaN on sapphire. Journal of Applied Physics 92, pages 786-792.
dc.relation.haspart R. Armitage, W. Hong, Q. Yang, H. Feick, J. Gebauer, E. R. Weber, S. Hautakangas, and K. Saarinen. 2003. Contributions from gallium vacancies and carbon-related defects to the "yellow luminescence" in GaN. Applied Physics Letters 82, pages 3457-3459.
dc.relation.haspart S. Hautakangas, V. Ranki, I. Makkonen, M. J. Puska, K. Saarinen, X. Xu, and D. C. Look. Direct experimental evidence of impurity decoration of Ga vacancies in GaN. Physical Review Letters, submitted for publication. [article5.pdf] © 2005 by authors and © 2005 American Physical Society. By permission.
dc.relation.haspart T. Paskova, P. P. Paskov, E. M. Goldys, E. Valcheva, V. Darakchieva, U. Södervall, M. Godlewski, M. Zielinski, S. Hautakangas, K. Saarinen, C. F. Carlström, Q. Wahab, and B. Monemar. 2004. Characterization of mass-transport grown GaN by hydride vapour-phase epitaxy. Journal of Crystal Growth 273, pages 118-128.
dc.subject.other Physics en
dc.title Impurity decoration of native vacancies in Ga and N sublattices of gallium nitride en
dc.type G5 Artikkeliväitöskirja fi
dc.description.version reviewed en
dc.contributor.department Department of Engineering Physics and Mathematics en
dc.contributor.department Teknillisen fysiikan ja matematiikan osasto fi
dc.subject.keyword gallium nitride en
dc.subject.keyword positron annihilation en
dc.subject.keyword vacancy en
dc.identifier.urn urn:nbn:fi:tkk-005216
dc.type.dcmitype text en
dc.type.ontasot Väitöskirja (artikkeli) fi
dc.type.ontasot Doctoral dissertation (article-based) en
dc.contributor.lab Laboratory of Physics en
dc.contributor.lab Fysiikan laboratorio fi

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