A dissociation mechanism for the [a+c] dislocation in GaN

Electron Microscopy and Analysis Group Conference 2013

Nellist, P.D.^1 ; Hirsch, P.B.^1 ; Rhode, S.^2 ; Horton, M.K.^3 ; Lozano, J.G.^1 ; Yasuhara, A.^4 ; Okunishi, E.^4 ; Zhang, S.^2 ; Sahonta, S.-L.^1 ; Kappers, M.J.^2 ; Humphreys, C.J.^2 ; Moram, M.A.^3

Department of Materials, University of Oxford, Parks Road, OX1 3PH Oxford, United Kingdom^1

Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, CB2 3QZ Cambridge, United Kingdom^2

Department of Materials, Imperial College London, Exhibition Road, SW7 2AZ London, United Kingdom^3

JEOL Ltd., EM Application Group, 1-2 Musashino 3-Chome, Akishima, Tokyo 196-8558, Japan^4

关键词: Atomic resolution;    Depth dependents;    Dislocation glide;    Dissociation mechanisms;    Dissociation reactions;    High-angle-annular-dark-field scanning transmission electron microscopes;    Loop analysis;    Mixed type;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/522/1/012037/pdf
DOI  :  10.1088/1742-6596/522/1/012037

来源: IOP

【 摘 要 】

Mixed-type [a+c] dislocations can be identified in atomic-resolution high-angle annular dark-field scanning transmission electron microscope images of GaN viewed along [0001] by use of a Burgers loop analysis and by observation of the depth-dependent displacements associated with the Eshelby twist. These dislocations are found to be able to dissociate resulting in a fault that lies perpendicular to the dislocation glide plane. Consideration of the bonding that occurs in such a fault allows the dissociation reaction to be proposed, and the proposed fault agrees with the experimental images when kinks are incorporated into the model.