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Exciton Dynamics in Droplet Epitaxial Quantum Dots Grown on (311)A Oriented Substrates
Version 1
: Received: 31 July 2020 / Approved: 2 August 2020 / Online: 2 August 2020 (12:35:59 CEST)
A peer-reviewed article of this Preprint also exists.
Abbarchi, M.; Mano, T.; Kuroda, T.; Sakoda, K. Exciton Dynamics in Droplet Epitaxial Quantum Dots Grown on (311)A-Oriented Substrates. Nanomaterials 2020, 10, 1833. Abbarchi, M.; Mano, T.; Kuroda, T.; Sakoda, K. Exciton Dynamics in Droplet Epitaxial Quantum Dots Grown on (311)A-Oriented Substrates. Nanomaterials 2020, 10, 1833.
Abstract
Droplet epitaxy allows the efficient fabrication of a plethora of 3D, III-V-based nanostructures on different crystalline orientations. Quantum dots grown on (311)A-oriented surface are obtained with record surface density, with or without a wetting layer. These are appealing features for quantum-dot lasing, thanks to the large density of quantum emitters and a truly 3D lateral confinement. However, the intimate photophysics of this class of nanostructures has not yet been investigated. Here we address the main optical and electronic properties of s-shell excitons in individual quantum dots grown on (311)A substrates with photoluminescence spectroscopy experiments. We show the presence of neutral exciton and biexciton as well as positive and negative charged excitons. We investigate the origins of spectral broadening, identifying them in spectral diffusion at low temperature and phonon-interaction at higher temperature, the presence of fine interactions between electron and hole spin, and a relevant heavy-hole/light-hole mixing. We interpret the level filling with a simple Poissonian model reproducing the power excitation dependence of the s-shell excitons. These results are relevant for the further improvement of this class of quantum emitters and their exploitation as single photon sources for low density samples as well as for efficient lasers for high density samples.
Keywords
III-V Quantum dots; Droplet Epitaxy; exciton dynamics; (311)A oriented substrate
Subject
Physical Sciences, Condensed Matter Physics
Copyright: This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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