Observation of depth-dependent atomic displacements related to dislocations in GaN by optical sectioning in the STEM

Electron Microscopy and Analysis Group Conference 2013

Lozano, J.G.^1 ; Guerrero-Lebrero, M.P.^2 ; Yasuhara, A.^3 ; Okinishi, E.^3 ; Zhang, S.^4 ; Humphreys, C.J.^4 ; Galindo, P.L.^2 ; Hirsch, P.B.^1 ; Nellist, P.D.^1

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

Departamento de Ingenieria Informatica, CASEM, Universidad de Cadiz, Pol. Rio San Pedro s/n, 11510 Puerto Real, Cadiz, Spain^2

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

Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge CB2 3QZ, United Kingdom^4

关键词: Aberration-corrected;    Atomic displacement;    Depth dependents;    Depth of field;    Eshelby;    GaN crystals;    Optical sectioning;    Scanning transmission electron microscopes;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/522/1/012048/pdf
DOI  :  10.1088/1742-6596/522/1/012048

来源: IOP

【 摘 要 】

We demonstrate that it is possible to observe depth-dependent atomic displacements in a GaN crystal due to the sufficiently small depth of field achievable in the aberration-corrected scanning transmission electron microscope. The depth-dependent displacements associated with the Eshelby twist of screw dislocations in GaN viewed end on are directly imaged, and makes possible the determination of the sign of the Burgers vector of the dislocation. The experimental results are in good agreement with theoretical images.