Wetting layer-assisted modification of in-plane-polarized transitions in strain-free GaAs/AlGaAs quantum dots

Abstract

In this work, the effects of wetting layer (WL) thickness on the electronic and transition properties of strain-free pyramid-shaped GaAs/Al0.3Ga0.7As quantum dots (QDs) coupled to a WL, which are relaxed from piezoelectric effect, are investigated. It is shown that the WL, which is usually ignored in the literature, severely influences properties, such as transition dipole moment and oscillator strength of QD/WL coupled structures. Two in-plane-polarized transitions of P-to-S and WL-to-P transitions were investigated. Although, the oscillator strength of P-to-S transition decreases with increasing the WL thickness, it still dominates the oscillator strength of WL-to-P transition. Also, an increasing trend for WL-to-P transition is shown with increasing the WL thickness. The results, which were compared with experimental data Wang et al. (2009), are of importance in QD-based devices such as lasers and photo-detectors, as well as harmonic generation.