Auger type relaxation of excitons in self assembled quantum dots via resonance scattering

We have investigated an Auger type mechanism of the relaxation of the carriers onto the deep levels of the self-assembled quantum dots (QD). Our analysis shows that resonant electron-hole collisions can lead to unexpectedly fast energy relaxation. Basic idea of the proposed mechanism is the Breit-Wigner type scattering of a delocalised particle with a particle trapped inside a dot. If energy of an incoming particle is close to the energy of a virtual two-particle state scattering crossections resonantly enhanced. We show that the number of resonances is sufficiently large leading to large average crossections. Realistic estimations for the In dots in the GaAs matrix shows that energy relaxation takes about 5-50 picosecond, which is comparable with experimental findings.