Comparative study of GaAs-based 1.5 micron-range InAs/InGaAs and InAs/InAlAs self-assembled quantum dots

Optical properties of self-organized QDs grown on thick metamorphic InGaAs layers with different In composition are studied. The dots are formed by an overgrowth of original InAs islands with thin InGaAs or InAlAs layers. Room temperature photoluminescence at 1.55 μm is demonstrated for the sample with 27% In composition in the matrix. The overgrowth with InAIAs layers permits to eliminate the wetting layer states and increase energy separation between QD ground and excited states.