Exciton thermal escape in symmetric InAs quantum dots in InGaAs/GaAs well structures

Abstract

The photoluminescence and its temperature dependence have been investigated for the ensembles of InAs quantum dots embedded in symmetric In 0.15 Ga 0.85 As/GaAs quantum wells with different PL intensities. The solution of the set of rate equations for exciton dynamics was used to analyze the nature of thermal activation energies of the QD photoluminescence quenching. It is revealed two different stages of thermally activated quenching of the QD PL intensity caused by thermal escape of excitons from the In 0.15 Ga 0.85 As/GaAs QW into the GaAs barrier and from the QDs into the QWs with their subsequent nonradiative recombination. The variety of activation energies of PL thermal quenching is discussed as well.

InAs Quantum Dots in Symmetric InGaAs/GaAs Quantum Wells

“…But in other QD structures the fitting parameter "a" and 'b' are different a little bit from the values in the bulk InAs crystal ( Table 3). The last fact testifies that the process of Ga/In inter diffusion takes place in these QD structures [33,[42][43][44]. Note that the process of Ga/In inter diffusion in studied structures passes non monotonically versus QD growth temperatures.…”

Multiexcited state study in InAs DWELL structures

“…Photoluminescence spectra were measured in the 80-300 K temperature range under the excitation of the 514.5 nm line of a cw Ar+-laser at an excitation power density of 1-1000 W/cm 2 . PL spectroscopy setup was presented earlier in [4,6]. The QD density estimated using atomic force microscope on uncapped satellite structures was 1.3 × 10 10 cm −2 .…”