Long exciton lifetimes in stacking-fault-free wurtzite GaAs nanowires
- Institut für Experimentelle und Angewandte Physik, Universität Regensburg, D-93040 Regensburg (Germany)
We present a combined photoluminescence and transmission electron microscopy study of single GaAs nanowires. Each wire was characterized both in microscopy and spectroscopy, allowing a direct correlation of the optical and the structural properties. By tuning the growth parameters, the nanowire crystal structure is optimized from a highly mixed zincblende–wurtzite structure to pure wurtzite. We find the latter one to be stacking-fault-free over nanowire lengths up to 4.1 μm. We observe the emission of purely wurtzite nanowires to occur only with polarization directions perpendicular to the wurtzite c{sup ^}-axis, as expected from the hexagonal unit cell symmetry. The free exciton recombination energy in the wurtzite structure is 1.518 eV at 5 K with a narrow linewidth of 4 meV. Most notably, these pure wurtzite nanowires display long carrier recombination lifetimes of up to 11.2 ns, exceeding reported lifetimes in bulk GaAs and state-of-the-art 2D GaAs/AlGaAs heterostructures.
- OSTI ID:
- 22402408
- Journal Information:
- Applied Physics Letters, Journal Name: Applied Physics Letters Journal Issue: 22 Vol. 105; ISSN APPLAB; ISSN 0003-6951
- Country of Publication:
- United States
- Language:
- English
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