Abstract
Abstract An unusual two-dimensional structure in hot-pressed wurtzite A1N, composed of a mixture of both curved and flat elements, is analysed by weak-beam and high-resolution electron microscopy. It is demonstrated that the structure, in its elementary form, is a ‘dome’-like faulted defect. This defect is characterized by a Frank-type dislocation loop containing a metal-vacancy-induced stacking fault in the basal plane with displacement Rp = (1/3) [1100] + 0·15[0001] and a curved faulted interface with displacement vector Rc = (1/3)[1100] + (1/2)[0001]. The elementary dome is found always pointing in the same direction, reflecting the lack of symmetry in the tetrahedral unit structure of A1N with respect to the basal plane. Condensation of supersaturated metal vacancies on both interfaces, combined with the segregation of impurities, mainly oxygen, only on the planar interface, is considered to be the driving force for the nucleation and growth of the structure.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.