We investigate strained In${}_x$Ga${}_{1-x}$As/GaAs and strain-free GaAs/Al${}_{0.3}$Ga${}_{0.7}$As quantum dots (QDs) grown on (110)-oriented substrates by means of atomic empirical pseudopotentials and configuration interaction. We find that there is a significant piezoelectric effect on the exciton fine structure splitting (FSS) in strained QDs due to the in-plane character of the electric field. The ground-state bright excitons in these QDs are polarized along the [001] and [$\overline{1}$10] crystal directions, and have large FSSs. The linear degree of polarization is large and decreases linearly with an increase in Ga content, while it is nearly zero and independent of Ga content in In${}_x$Ga${}_{1-x}$As/GaAs QDs with similar shape and size grown on (001) substrates.

• Received 12 July 2013

DOI:https://doi.org/10.1103/PhysRevB.88.075430