GaAs first-spacer-layer thickness dependence of polarized photoluminescence properties of closely-stacked InAs/GaAs quantum dots with long-wavelength emission

We investigated effects of the GaAs first-spacer-layer thickness on polarized photoluminescence properties of closely-stacked InAs/GaAs quantum dots (QDs) with long-wavelength emission. As the GaAs first-spacer-layer thickness was decreased, the [001]-polarization component increased relative to the [110] component due to an enhancement of the electronic coupling between the QDs along the stacking direction. In addition, as the GaAs first-spacer-thickness was decreased, the emission from the incompletely coupled QDs that failed to couple was suppressed. Therefore, the polarization properties of closely-stacked QDs are very sensitive to the GaAs first-spacer-thickness.