Title: Geometrical impact on the optical polarization of droplet epitaxial quantum dots
Authors: Liao, Yu-Huai
Liao, Chien-Chih
Ku, Chih-Hao
Chang, Yu-Chen
Cheng, Shun-Jen
Jo, Masafumi
Kuroda, Takashi
Mano, Takaaki
Abbarchi, Marco
Sakoda, Kazuaki
Department of Electrophysics
Issue Date: 17-Sep-2012
Abstract: We report on experimental and theoretical investigations of the optical anisotropy of GaAs/AlGaAs quantum dots grown by droplet epitaxy. With in situ annealing in the growth, the shape of quantum dots is systematically controlled from a tall and laterally symmetric shape to a flat and laterally elongated one. Photoluminescence spectroscopy demonstrates an uncommon observation: the more elongated the quantum dots, the lower the degree of linear polarization. Theoretical analysis based on a four-band k center dot p theory reveals a substantial impact of vertical confinement on the valence heavy-hole and light-hole mixing, which leads to the enhancement of polarization anisotropy for taller quantum dots. The influence of Coulomb interactions on polarization anisotropy is studied by using the partial configuration interaction method, and is shown to reduce the polarization anisotropy through the mixing of single-particle configurations with different symmetries.
URI: http://dx.doi.org/10.1103/PhysRevB.86.115323
ISSN: 1098-0121
DOI: 10.1103/PhysRevB.86.115323
Volume: 86
Issue: 11
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