GaAs/AlGaAs heterostructure nanowires studied by cathodoluminescence

Jessica Bolinsson, Martin Ek, Johanna Trägårdh, Kilian Mergenthaler, Daniel Jacobsson, Mats-Erik Pistol, Lars Samuelson, Anders Gustafsson

Research output: Contribution to journalArticlepeer-review


In this report we explore the structural and optical properties of GaAs/AlGaAs heterostructure nanowires grown by metalorganic vapour phase epitaxy using gold seed-particles. The optical studies were done by low-temperature cathodoluminescence (CL) in a scanning electron microscope (SEM). We perform a systematic investigation of how the nanowire growth-temperature affects the total photon emission, and variations in the emission energy and intensity along the length of the nanowires. The morphology and crystal structures of the nanowires were investigated using SEM and transmission electron microscopy (TEM). In order to correlate specific photon emission characteristics with variations in the nanowire crystal structure directly, TEM and spatially resolved CL measurements were performed on the same individual nanowires. We found that the main emission energy was located at around 1.48 eV, and that the emission intensity was greatly enhanced when increasing the GaAs nanowire core growth temperature. The data strongly suggests that this emission energy is related to rotational twins in the GaAs nanowire core. Our measurements also show that radial overgrowth by GaAs on the GaAs nanowire core can have a deteriorating effect on the optical quality of the nanowires. Finally, we conclude that an in situ pre-growth annealing step at a sufficiently high temperature significantly improves the optical quality of the nanowires.
Original languageEnglish
Pages (from-to)473-490
JournalNano Reseach
Issue number4
Publication statusPublished - 2014

Subject classification (UKÄ)

  • Condensed Matter Physics
  • Nano Technology
  • Chemical Sciences

Free keywords

  • GaAs/AlGaAs core shell nanowires
  • metalorganic vapour phase epitaxy
  • (MOVPE)
  • cathodoluminescence
  • twin defects
  • transmission electron
  • microscopy


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