Localized excitons in InAs self-assembled quantum dots embedded in InGaAs/GaAs multi-quantum wells

Abstract

The temperature-dependent photoluminescence (PL) spectra of highly uniform self-assembled InAs quantum dots (QDs) embedded in In0.15Ga0.8As/GaAs multi-quantum well (MQW) structures have been investigated. Spectral peak shift and PL temperature quenching for ground state (GS) and first excited state (1ES) optical transitions in the range 12–220 K are analyzed. Small FWHM values equal to 37 and 27 meV at 12 K characterize the GS and 1ES transitions, respectively. For the highly uniform QDs no unusual decrease of the FWHM at low temperatures was seen that would be connected with the redistribution of carriers between the QDs. The activation energies of the PL temperature quenching processes for GS and 1ES in InAs QDs are found to be the same, about 50–52 meV. The reasons for the same GS and 1ES thermal activation energies in InAs self-assembled QDs are discussed.