GaAs/AlGaAs heterostructure nanowires studied by cathodoluminescence
Författare
Summary, in English
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.
Publiceringsår
2014
Språk
Engelska
Sidor
473-490
Publikation/Tidskrift/Serie
Nano Reseach
Volym
7
Issue
4
Länkar
Dokumenttyp
Artikel i tidskrift
Förlag
Springer
Ämne
- Condensed Matter Physics
- Nano Technology
- Chemical Sciences
Nyckelord
- GaAs/AlGaAs core shell nanowires
- metalorganic vapour phase epitaxy
- (MOVPE)
- cathodoluminescence
- twin defects
- transmission electron
- microscopy
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1998-0124