title: Effect of screw threading dislocations and inverse domain boundaries in GaN on the shape of reciprocal-space maps.
abstract: The microstructure of polar GaN layers, grown by upgraded high-temperature vapour phase epitaxy on [001]-oriented sapphire substrates, was studied by means of high-resolution X-ray diffraction and transmission electron microscopy. Systematic differences between reciprocal-space maps measured by X-ray diffraction and those which were simulated for different densities of threading dislocations revealed that threading dislocations are not the only microstructure defect in these GaN layers. Conventional dark-field transmission electron microscopy and convergent-beam electron diffraction detected vertical inversion domains as an additional microstructure feature. On a series of polar GaN layers with different proportions of threading dislocations and inversion domain boundaries, this contribution illustrates the capability and limitations of coplanar reciprocal-space mapping by X-ray diffraction to distinguish between these microstructure features.
authors.affiliation: Institute of Materials Science, TU Bergakademie Freiberg, Gustav-Zeuner-Strasse 5, Freiberg 09599, Germany.
authors.forename: Mykhailo
authors.identifier: https://orcid.org/0000-0001-8237-9795
authors.initials: M
authors.lastname: Barchuk
authors.affiliation: Institute of Materials Science, TU Bergakademie Freiberg, Gustav-Zeuner-Strasse 5, Freiberg 09599, Germany.
authors.forename: Mykhaylo
authors.initials: M
authors.lastname: Motylenko
authors.affiliation: Institute of Nonferrous Metallurgy and Purest Materials, TU Bergakademie Freiberg, Leipziger Strasse 34, Freiberg 09599, Germany.
authors.forename: Gleb
authors.initials: G
authors.lastname: Lukin
authors.affiliation: Institute of Nonferrous Metallurgy and Purest Materials, TU Bergakademie Freiberg, Leipziger Strasse 34, Freiberg 09599, Germany.
authors.forename: Olf
authors.initials: O
authors.lastname: Pätzold
authors.affiliation: Institute of Materials Science, TU Bergakademie Freiberg, Gustav-Zeuner-Strasse 5, Freiberg 09599, Germany.
authors.forename: David
authors.identifier: https://orcid.org/0000-0003-2411-7425
authors.initials: D
authors.lastname: Rafaja
keywords: X-ray diffraction; gallium nitride; inversion domain boundaries; threading dislocations; transmission electron microscopy