Photoluminescence up-conversion in single self-assembled InAs/GaAs quantumdots - art. no. 207401

Microphotoluminescence measurements under ew excitation reveal the existenc e of a strong photoluminescence up-conversion from single InAs/GaAs self-as sembled quantum dots and also from the InAs wetting layer. Excitation spect roscopy of the up-converted photoluminescence signal shows identical featur es from the wetting layer and the single quantum dots, i.e., a band tail co ming from the deep states localized at the rough interfaces of the wetting layer quantum well. This observation of photoluminescence up-conversion dem onstrates the influence on the quantum dot properties of the environment, a nd highlights the limitations of the artificial atom model for a semiconduc tor quantum dot.