Dislocations in AlGaN: core structure, atom segregation, and optical properties

Massabuau, Fabien C-P. and Rhode, Sneha L. and Horton, Matthew K. and O'Hanlon, Thomas J. and Kovacs, Andras and Zielinski, Marcin S. and Kappers, Menno J. and Dunin-Borkowski, Rafal E. and Humphreys, Colin J. and Oliver, Rachel A. (2017) Dislocations in AlGaN: core structure, atom segregation, and optical properties. Nano Letters, 17 (8). pp. 4846-4852. ISSN 1530-6992 (https://doi.org/10.1021/acs.nanolett.7b01697)

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Abstract

We conducted a comprehensive investigation of dislocations in Al0.46Ga0.54N. Using aberration-corrected scanning transmission electron microscopy and energy dispersive X-ray spectroscopy, the atomic structure and atom distribution at the dislocation core have been examined. We report that the core configuration of dislocations in AlGaN is consistent with that of other materials in the III-Nitride system. However, we observed that the dissociation of mixed-type dislocations is impeded by alloying GaN with AlN, which is confirmed by our experimental observation of Ga and Al atom segregation in the tensile and compressive parts of the dislocations, respectively. Investigation of the optical properties of the dislocations shows that the atom segregation at dislocations has no significant effect on the intensity recorded by cathodoluminescence in the vicinity of the dislocations. These results are in contrast with the case of dislocations in In0.09Ga0.91N where segregation of In and Ga atoms also occurs but results in carrier localization limiting non-radiative recombination at the dislocation. This study therefore sheds light on why InGaN-based devices are generally more resilient to dislocations than their AlGaN-based counterparts.

ORCID iDs

Massabuau, Fabien C-P. ORCID logoORCID: https://orcid.org/0000-0003-1008-1652, Rhode, Sneha L., Horton, Matthew K., O'Hanlon, Thomas J., Kovacs, Andras, Zielinski, Marcin S., Kappers, Menno J., Dunin-Borkowski, Rafal E., Humphreys, Colin J. and Oliver, Rachel A.;
  • Item type:Article
    ID code:69879
    Dates:
    Date
    Event
    9 August 2017
    Published
    18 July 2017
    Published Online
    14 July 2017
    Accepted
    Notes:his document is the Accepted Manuscript version of a Published Work that appeared in final form in Nano Letters, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://doi.org/10.1021/acs.nanolett.7b01697.
    Subjects:Science > Physics
    Department:Faculty of Science > Physics
    Depositing user: Pure Administrator
    Date deposited:20 Sep 2019 13:26
    Last modified:11 Nov 2024 12:26
    Related URLs:
    URI:https://strathprints.strath.ac.uk/id/eprint/69879
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