Breakdown of the phonon bottleneck effect in self-assembled quantum dots

Spectral and temporal behavior of photoluminescence of site-selectively excited InP self-assembled quantum dots were studied in external electric fields. External electric field accelerates the nonradiative relaxation and competing fast phonon mediated relaxation processes make prominent structures in the static spectra, The spectra agree with the time-resolved spectra around the time zero and reflect the phonon relaxation rate. Acoustic phonon mediated carrier relaxation is much faster than predicted theoretically, The increases of the excitation intensity, temperature, electric current and charging of quantum dots accelerate the relaxation of the carriers in quantum dots, indicating build-up of Auger-like processes. This observation demonstrates the breakdown of the predicted phonon bottleneck effect not only at the condition for the practical application of the quantum dots but also at low temperature and under weak excitation.