Carrier capture processes in strain-induced InxGa1-xAs/GaAs quantum dot structures

We investigate carrier capture processes in strain-induced quantum dot stru ctures. The quantum dots consist of a near-surface InGaAs/GaAs quantum well in which a lateral confining potential is generated by the strain from InP stressor islands grown on the sample surface. Using photoluminescence spec troscopy, we show that the rate of carrier capture into the quantum dots in creases dramatically when the energetic depth of the confinement potential is reduced by enlarging the quantum well/surfate separation D. While carrie rs in the quantum well region between the quantum dots are found to experie nce D-dependent nonradiative surface recombination, this process seems to b e negligible for carriers in the quantum dots, presumably due to the protec ting InP islands.