Fine structure splitting reduction in droplet epitaxy GaAs quantum dots grown on (111)A surface

Abstract

In this contribution we compare the geometrical symmetry of self-assembled GaAs quantum dots (QDs) grown by a refined droplet epitaxy (DE) method on (100) and (111)A AlGaAs substrate. By atomic force microscopy (AFM) we study the morphology of the QDs and by micro-photoluminescence spectroscopy (μPL) we compare the dependence of the fine structure splitting on QD size and shape. We show that: i) the refined DE enhances the elongation of QDs grown on (100) AlGaAs substrate increasing the fine structure splitting; ii) by growing the QDs on the (111)A AlGaAs surface it is possible to recover a good geometrical circular symmetry obtaining a small value of the fine structure splitting . © 2010 IOP Publishing Ltd.