Abstract
Photoluminescence (PL) properties of self-organized quantum dots (QDs) in a vertically aligned double-layer InAs/GaAs QD structure are studied as a function of temperature from 10 to 290 K. The QDs in a sample with a 1.8 ML InAs seed layer and a second 2.4 ML InAs layer are found to self-organize in pairs of unequal sized QDs with clearly discernible ground-states transition energy. The unusual temperature behavior of the PL for such asymmetrical QD pairs provides clear evidence for carrier transfer from smaller to larger QDs by means of a nonresonant multiphonon-assisted tunneling process in the case of interlayer transfer and through carrier thermal emission and recapture within one layer.
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