Polarity-driven 3-fold symmetry of GaAs/AlGaAs core multishell nanowires

Changlin Zheng, Jennifer Wong-Leung, Qiang Gao, Hark Hoe Tan, Chennupati Jagadish, Joanne Etheridge

Research output: Contribution to journalArticleResearchpeer-review

Abstract

AlGaAs/GaAs quantum well heterostructures based on core-multishell nanowires exhibit excellent optical properties which are acutely sensitive to structure and morphology. We characterize these heterostructures and observe them to have 3-fold symmetry about the nanowire axis. Using aberration-corrected annular dark field scanning transmission electron microscopy (ADF-STEM), we measure directly the polarity of the crystal structure and correlate this with the shape and facet orientation of the GaAs core, quantum wells and cap, and the width of radial Al-rich bands. We discuss how the underlying polarity of the crystal structure drives the growth of these heterostructures with a 3-fold symmetry resulting in a nonuniform GaAs quantum well tube and AlGaAs shell. These observations suggest that the AlGaAs growth rate is faster along the B compared to the A directions and/or that there is a polarity driven surface reconstruction generating AlGaAs growth fronts inclined to the 110 planes. In contrast, the observations suggest that the opposite is true for the GaAs growth, with the preferred surface reconstruction plane being parallel to 110 and an apparent faster growth rate along the A. This two-dimensional layer growth of the nanowire multishells strongly depends on the surface energies and surface reconstruction of the facets which are related to the crystal polarity and lead to the 3-fold symmetry observed here.
Original languageEnglish
Pages (from-to)3742 - 3748
Number of pages7
JournalNano Letters
Volume13
DOIs
Publication statusPublished - 2013

Cite this

Zheng, C., Wong-Leung, J., Gao, Q., Tan, H. H., Jagadish, C., & Etheridge, J. (2013). Polarity-driven 3-fold symmetry of GaAs/AlGaAs core multishell nanowires. Nano Letters, 13, 3742 - 3748. https://doi.org/10.1021/nl401680k
Zheng, Changlin ; Wong-Leung, Jennifer ; Gao, Qiang ; Tan, Hark Hoe ; Jagadish, Chennupati ; Etheridge, Joanne. / Polarity-driven 3-fold symmetry of GaAs/AlGaAs core multishell nanowires. In: Nano Letters. 2013 ; Vol. 13. pp. 3742 - 3748.
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abstract = "AlGaAs/GaAs quantum well heterostructures based on core-multishell nanowires exhibit excellent optical properties which are acutely sensitive to structure and morphology. We characterize these heterostructures and observe them to have 3-fold symmetry about the nanowire axis. Using aberration-corrected annular dark field scanning transmission electron microscopy (ADF-STEM), we measure directly the polarity of the crystal structure and correlate this with the shape and facet orientation of the GaAs core, quantum wells and cap, and the width of radial Al-rich bands. We discuss how the underlying polarity of the crystal structure drives the growth of these heterostructures with a 3-fold symmetry resulting in a nonuniform GaAs quantum well tube and AlGaAs shell. These observations suggest that the AlGaAs growth rate is faster along the B compared to the A directions and/or that there is a polarity driven surface reconstruction generating AlGaAs growth fronts inclined to the 110 planes. In contrast, the observations suggest that the opposite is true for the GaAs growth, with the preferred surface reconstruction plane being parallel to 110 and an apparent faster growth rate along the A. This two-dimensional layer growth of the nanowire multishells strongly depends on the surface energies and surface reconstruction of the facets which are related to the crystal polarity and lead to the 3-fold symmetry observed here.",
author = "Changlin Zheng and Jennifer Wong-Leung and Qiang Gao and Tan, {Hark Hoe} and Chennupati Jagadish and Joanne Etheridge",
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Zheng, C, Wong-Leung, J, Gao, Q, Tan, HH, Jagadish, C & Etheridge, J 2013, 'Polarity-driven 3-fold symmetry of GaAs/AlGaAs core multishell nanowires', Nano Letters, vol. 13, pp. 3742 - 3748. https://doi.org/10.1021/nl401680k

Polarity-driven 3-fold symmetry of GaAs/AlGaAs core multishell nanowires. / Zheng, Changlin; Wong-Leung, Jennifer; Gao, Qiang; Tan, Hark Hoe; Jagadish, Chennupati; Etheridge, Joanne.

In: Nano Letters, Vol. 13, 2013, p. 3742 - 3748.

Research output: Contribution to journalArticleResearchpeer-review

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T1 - Polarity-driven 3-fold symmetry of GaAs/AlGaAs core multishell nanowires

AU - Zheng, Changlin

AU - Wong-Leung, Jennifer

AU - Gao, Qiang

AU - Tan, Hark Hoe

AU - Jagadish, Chennupati

AU - Etheridge, Joanne

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N2 - AlGaAs/GaAs quantum well heterostructures based on core-multishell nanowires exhibit excellent optical properties which are acutely sensitive to structure and morphology. We characterize these heterostructures and observe them to have 3-fold symmetry about the nanowire axis. Using aberration-corrected annular dark field scanning transmission electron microscopy (ADF-STEM), we measure directly the polarity of the crystal structure and correlate this with the shape and facet orientation of the GaAs core, quantum wells and cap, and the width of radial Al-rich bands. We discuss how the underlying polarity of the crystal structure drives the growth of these heterostructures with a 3-fold symmetry resulting in a nonuniform GaAs quantum well tube and AlGaAs shell. These observations suggest that the AlGaAs growth rate is faster along the B compared to the A directions and/or that there is a polarity driven surface reconstruction generating AlGaAs growth fronts inclined to the 110 planes. In contrast, the observations suggest that the opposite is true for the GaAs growth, with the preferred surface reconstruction plane being parallel to 110 and an apparent faster growth rate along the A. This two-dimensional layer growth of the nanowire multishells strongly depends on the surface energies and surface reconstruction of the facets which are related to the crystal polarity and lead to the 3-fold symmetry observed here.

AB - AlGaAs/GaAs quantum well heterostructures based on core-multishell nanowires exhibit excellent optical properties which are acutely sensitive to structure and morphology. We characterize these heterostructures and observe them to have 3-fold symmetry about the nanowire axis. Using aberration-corrected annular dark field scanning transmission electron microscopy (ADF-STEM), we measure directly the polarity of the crystal structure and correlate this with the shape and facet orientation of the GaAs core, quantum wells and cap, and the width of radial Al-rich bands. We discuss how the underlying polarity of the crystal structure drives the growth of these heterostructures with a 3-fold symmetry resulting in a nonuniform GaAs quantum well tube and AlGaAs shell. These observations suggest that the AlGaAs growth rate is faster along the B compared to the A directions and/or that there is a polarity driven surface reconstruction generating AlGaAs growth fronts inclined to the 110 planes. In contrast, the observations suggest that the opposite is true for the GaAs growth, with the preferred surface reconstruction plane being parallel to 110 and an apparent faster growth rate along the A. This two-dimensional layer growth of the nanowire multishells strongly depends on the surface energies and surface reconstruction of the facets which are related to the crystal polarity and lead to the 3-fold symmetry observed here.

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