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Direct observation of depth-dependent atomic displacements associated with dislocations in gallium nitride.

Authors
  • Lozano, J G1
  • Yang, H1
  • Guerrero-Lebrero, M P2
  • D'Alfonso, A J3
  • Yasuhara, A4
  • Okunishi, E4
  • Zhang, S5
  • Humphreys, C J5
  • Allen, L J3
  • Galindo, P L2
  • Hirsch, P B1
  • Nellist, P D1
  • 1 Department of Materials, University of Oxford, OX1 3PH Oxford, United Kingdom. , (United Kingdom)
  • 2 Departamento de Ingeniería Informática, CASEM, Universidad de Cadiz, Polígono Rio San Pedro s/n, 11510 Puerto Real (Cadiz), Spain. , (Spain)
  • 3 School of Physics, University of Melbourne, Parkville, Victoria 3010, Australia. , (Australia)
  • 4 JEOL Ltd., 1-2 Musashino 3-Chome, Akishima, 196-8558 Tokyo, Japan. , (Japan)
  • 5 Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, CB3 0FS Cambridge, United Kingdom. , (United Kingdom)
Type
Published Article
Journal
Physical Review Letters
Publisher
American Physical Society
Publication Date
Sep 26, 2014
Volume
113
Issue
13
Pages
135503–135503
Identifiers
PMID: 25302902
Source
Medline
License
Unknown

Abstract

We demonstrate that the aberration-corrected scanning transmission electron microscope has a sufficiently small depth of field to observe depth-dependent atomic displacements in a crystal. The depth-dependent displacements associated with the Eshelby twist of dislocations in GaN normal to the foil with a screw component of the Burgers vector are directly imaged. We show that these displacements are observed as a rotation of the lattice between images taken in a focal series. From the sense of the rotation, the sign of the screw component can be determined.

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