Effects of variable anisotropic-strain on the emission of neutral excitons confined in epitaxial quantum dots

TL;DR

This study investigates how elastic anisotropic biaxial strain influences the optical properties of neutral excitons in semiconductor quantum dots, revealing significant polarization rotation and fine structure splitting changes.

Contribution

It demonstrates that small anisotropic strain fields can dramatically alter the electronic and optical properties of quantum dots, with a continuum model explaining the underlying mechanisms.

Findings

Polarization of emitted light can rotate by up to 80 degrees.

Fine structure splitting varies by several tens of microelectronvolts.

Strain fields of a few permill can significantly modify quantum dot electronic structure.

Abstract

We study the effect of elastic anisotropic biaxial strain on the light emitted by neutral excitons confined in different kinds of semiconductor quantum dots (QDs). We find that the light polarization rotates by up to 80 degree and the excitonic fine structure splitting varies by several tens of $\mu$eVs as the strain is varied. By means of a continuum model we mainly ascribe the observed effects to substantial changes of the hole wave function. These results show that strain-fields of a few permill magnitude are suffcient to dramatically modify the electronic structure of QDs.