Photoluminescence studies of InAs/GaAs quantum dots covered by InGaAs layers

Photoluminescence (PL), PL excitation (PLE), and time-resolved PL were used to study effects of InGaAs layers on the optical properties of InAs/GaAs quantum dots (QDs). A rich fine structure in the excited states of confined excitons (up to n = 4 quantum states) was observed, providing useful information to study the quantum states in the InAs/GaAs QDs. A significant redshift of the PL peak energy for the QDs covered by InGaAs layers was observed, attributing to the decrease of the QD strain and the lowing of the quantum confinement.