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

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

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 w...

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Bibliographic Details
Main Authors: Lozano, J, Yang, H, Guerrero-Lebrero, M, D'Alfonso, A, Yasuhara, A, Okunishi, E, Zhang, S, Humphreys, C, Allen, L, Galindo, P, Hirsch, P, Nellist, P
Format: Journal article
Language:English
Published: American Physical Society 2014
Description
Summary: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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