Spatially-resolved luminescence and crystal structure of single core–shell nanowires measured in the as-grown geometry Academic Article uri icon

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abstract

  • We report on the direct correlation between the structural and optical properties of single, as-grown core-multi-shell GaAs/In0.15Ga0.85As/GaAs/AlAs/GaAs nanowires. Fabricated by molecular beam epitaxy on a pre-patterned Si(111) substrate, on a row of well separated nucleation sites, it was possible to access individual nanowires in the as-grown geometry. The polytype distribution along the growth axis of the nanowires was revealed by synchrotron-based nanoprobe x-ray diffraction techniques monitoring the axial 111 Bragg reflection. For the same nanowires, the spatially-resolved emission properties were obtained by cathodoluminescence hyperspectral linescans in a scanning electron microscope. Correlating both measurements, we reveal a blueshift of the shell quantum well emission energy combined with an increased emission intensity for segments exhibiting a mixed structure of alternating wurtzite and zincblende stacking compared with the pure crystal polytypes. The presence of this mixed structure was independently confirmed by cross-sectional transmission electron microscopy.

authors

  • AlHassan, Ali
  • Lähnemann, J
  • Leake, S
  • Küpers, H
  • Niehle, M
  • Bahrami, D
  • Bertram, F
  • Lewis, Ryan
  • Davtyan, A
  • Schülli, TU
  • Geelhaar, L
  • Pietsch, U

publication date

  • May 22, 2020