Effects of charged defects on the electronic and optical properties of self-assembled quantum dots

We investigate the effects of point charge defects on the single-particle electronic structure, emission energies, fine structure splitting, and oscillator strengths of excitonic transitions in strained In0.6Ga0.4As/GaAs and strain-free GaAs/Al0.3Ga0.7As quantum dots. We find that the charged defects significantly modify the single-particle electronic structure and excitonic spectra in both strained and strain-free structures. However, the excitonic fine structure splitting, polarization anisotropy, and polarization direction in strained quantum dots remain nearly unaffected, while significant changes are observed for strain-free quantum dots.