Dislocation contrast in electron channelling contrast images as projections of strain-like components

Pascal, E. and Hourahine, B. and Naresh-Kumar, G. and Mingard, K. and Trager-Cowan, C. (2018) Dislocation contrast in electron channelling contrast images as projections of strain-like components. Materials Today: Proceedings, 5 (Issue ). 14652–14661. ISSN 2214-7853 (https://doi.org/10.1016/j.matpr.2018.03.057)

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Abstract

The forward scattering geometry in the scanning electron microscope enables the acquisition of electron channelling contrast imaging (ECCI) micrographs. These images contain diffraction information from the beam of electrons “channelling in” into the sample. Since small, localised strains strongly affect the electron diffraction, defects which introduce lattice displacement in the region of the surface the electron beam is interacting with will be revealed as district variation in backscattered electron intensity. By acquiring multiple images from the same area in different diffraction conditions and comparing them against modelled predictions of defect strain sampled by diffraction, it is possible to characterise these defects. Here we discuss the relation between the elastic strain introduced by a threading dislocation intersecting the surface and the contrast features observed in the electron channelling contrast image of that region. Preliminary simulated channelling contrast images are shown for dislocations with known line direction and Burgers vectors using a two-beam dynamical diffraction model. These are demonstrated to be in qualitative agreement with measured images of dislocated polar wurtzite GaN acquired with two different diffraction condition.

ORCID iDs

Pascal, E. ORCID logoORCID: https://orcid.org/0000-0002-6785-986X, Hourahine, B. ORCID logoORCID: https://orcid.org/0000-0002-7667-7101, Naresh-Kumar, G. ORCID logoORCID: https://orcid.org/0000-0002-9642-8137, Mingard, K. and Trager-Cowan, C. ORCID logoORCID: https://orcid.org/0000-0001-8684-7410;
  • Item type:Article
    ID code:63048
    Dates:
    Date
    Event
    12 June 2018
    Published
    3 July 2017
    Accepted
    February 2017
    Submitted
    Keywords:electron channelling contrast imaging (ECCI), dislocations, scanning electron microscope (SEM), image simulation, defect imaging, Physics, Physics and Astronomy(all)
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Technology and Innovation Centre > Photonics
    Depositing user: Pure Administrator
    Date deposited:25 Jan 2018 12:48
    Last modified:16 Aug 2022 02:37
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/63048
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