Manipulating fine structure splitting in semiconductor quantum dots

Abstract

We perform million-atom empirical pseudopotential calculations of fine structure splitting (FSS) in realistic InAsP/InP and InGaAs/GaAs QD structures. We find that in alloy In(Ga) As self-assembled QDs (001) there exist a lower bound to the tuning of FSS by applying uniaxial stress due to an anticrossing of the excitonic lines, while in pure InAs self- assembled QDs (001) the FSS goes through zero to negative values due to the crossing of latter. We further predict that semiconductor nanostructures grown along the [111] direction such as self-assembled quantum dots or nanowire quantum dots have a vanishing FSS on grounds of their symmetry and are therefore ideal candidates for the generation of entangled photon pairs. PU - IOP PUBLISHING LTD PI - BRISTOL PA - DIRAC HOUSE, TEMPLE BACK, BRISTOL BS1 6BE, ENGLAND