Abstract
A detailed study of the -factor anisotropy of electrons and holes in InAs/ self-assembled quantum dots emitting in the telecom spectral range of (around 0.8 eV photon energy) is performed by time-resolved pump-probe ellipticity technique using a superconducting vector magnet. All components of the -factor tensors are measured, including their spread in the quantum dot (QD) ensemble. Surprisingly, the electron factor shows a large anisotropy changing from to between directions perpendicular and parallel to the dot growth axis, respectively, at an energy of 0.82 eV. The hole -factor anisotropy at this energy is even stronger: and . On the other hand, the in-plane anisotropies of electron and hole factors are small. The pronounced out-of-plane anisotropy is also observed for the spread of the factors, determined from the spin dephasing time. The hole longitudinal factors are described with a theoretical model that allows us to estimate the QD parameters. We find that the QD height-to-diameter ratio increases while the indium composition decreases with increasing QD emission energy.
- Received 7 December 2015
- Revised 11 February 2016
DOI:https://doi.org/10.1103/PhysRevB.93.125302
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