We compare the asymmetry-induced exchange splitting delta_1 of the bright-exciton ground-state doublet in self-assembled (In,Ga)As/GaAs quantum dots, determined by Faraday rotation, with its homogeneous linewidth gamma, obtained from the radiative decay in time-resolved photoluminescence. Post-growth thermal annealing of the dot structures leads to a considerable increase of the homogeneous linewidth, while a strong reduction of the exchange splitting is simultaneously observed. The annealing can be tailored such that delta_1 and gamma become comparable, whereupon the carriers are still well confined. This opens the possibility to observe polarization entangled photon pairs through the biexciton decay cascade.
@article{arxiv.physics/0601107,
title = {Tailored quantum dots for entangled photon pair creation},
author = {A. Greilich and M. Schwab and T. Berstermann and T. Auer and R. Oulton and D. R. Yakovlev and M. Bayer and V. Stavarache and D. Reuter and A. Wieck},
journal= {arXiv preprint arXiv:physics/0601107},
year = {2009}
}