InAs quantum dots coupled with strained InGaAs/GaAs coupled quantum-wells

We have studied the coupling between the InAs quantum dots and coupled quantum wells strained by the InAs quantum dots (i.e. coupled-quantum-well dots) by measuring photoluminescence spectra. By comparing the photoluminescence spectra of the coupled-quantum-well dots in which either the narrow well or wide well is grown next to the InAs quantum dots, we have evidenced the spatially inhomogeneous strains applied by the InAs quantum dots on the coupled quantum wells. Moreover, we have also investigated the three coupling regimes, i.e. when the dot level is higher than, lower than, and aligned to the lowest quantum-well transition. Based on our measurements, we conclude that the optical properties for the coupled-quantum-well dots have been significantly improved over the quantum dots.