Cathodoluminescence visualisation of local thickness variations of GaAs/AlGaAs quantum-well tubes on nanowires

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

Research output: Contribution to journalArticleResearchpeer-review

Abstract

We present spatially and spectrally resolved emission from nanowires with a thin radial layer of GaAs embedded in AlGaAs barriers, grown radially around taper-free GaAs cores. The GaAs layers are thin enough to show quantization, and are quantum wells. Due to their shape, they are referred to as quantum well tubes (QWTs). We have investigated three different nominal QWT thicknesses: 1.5, 2.0, and 6.0 nm. They all show average emission spectra from the QWT with an energy spread corresponding to a thickness variation of 30%. We observe no thickness gradient along the length of the nanowires. Individual NWs show a number of peaks, corresponding to different QW thicknesses. Apart from the thinnest QWT, the integrated emission from the QWTs shows homogeneous emission intensity along the NW. The thinnest QWTs show patchy emission patterns due to the incomplete coverage of the QWT. We observe a few NWs with larger diameters. The QWTs in these NWs show spatially resolved variations across the NW. An increase in the local thickness of the QWT at the corners blocks the diffusion of carriers from facet to facet, thereby enabling us to visualise the thickness variations of the radial quantum wells.

Original languageEnglish
Article number424001
Number of pages9
JournalNanotechnology
Volume31
Issue number42
DOIs
Publication statusPublished - 16 Oct 2020

Keywords

  • cathodoluminescence
  • hyperspectral imaging
  • nanowires
  • quantum well tubes

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