Effective phonon bottleneck in the carrier thermalization of InAs/GaAs quantum dots

We present a detailed study of the dependence of the spectral characteristics of quasiresonantly excited InAs/GaAs quantum dots on electronic structure, temperature, and hydrogen content. Multiphonon resonances dominate the resonantly excited emission spectra. Such multiphonon resonances are attributed to the competition between two different channels ruling carrier thermalization in an ensemble of quantum dots: decay between polaronic states and efficient nonradiative intradot decay. This supports an effective "phonon bottleneck" in quantum dots, which is only partially relaxed by the presence of a fast polaron thermalization channel.