Nanoscale Research Letters (Jul 2019)

Electron Tomography of Pencil-Shaped GaN/(In,Ga)N Core-Shell Nanowires

  • Lars Nicolai,
  • Žarko Gačević,
  • Enrique Calleja,
  • Achim Trampert

DOI
https://doi.org/10.1186/s11671-019-3072-1
Journal volume & issue
Vol. 14, no. 1
pp. 1 – 10

Abstract

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Abstract The three-dimensional structure of GaN/(In,Ga)N core-shell nanowires with multi-faceted pencil-shaped apex is analyzed by electron tomography using high-angle annular dark-field mode in a scanning transmission electron microscope. Selective area growth on GaN-on-sapphire templates using a patterned mask is performed by molecular beam epitaxy to obtain ordered arrays of uniform nanowires. Our results of the tomographic reconstruction allow the detailed determination of the complex morphology of the inner (In,Ga)N multi-faceted shell structure and its deviation from the perfect hexagonal symmetry. The tomogram unambiguously identifies a dot-in-a-wire configuration at the nanowire apex including the exact shape and size, as well as the spatial distribution of its chemical composition.

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