Role of defect states on Auger processes in resonantly pumped CdSe nanorods

The authors investigated, by femtosecond pump-probe measurements, the effects on Auger and trapping processes of excitation resonant (R) to the 1S absorption in CdSe nanorods. They demonstrate that R pumping allows one to avoid exciton trapping in high energy defect states and that the presence of empty defect states leads to an enhancement of the Auger relaxation, with respect to the pumping at energies high above the band gap. Moreover, they show that, despite the Auger enhancement, R pumping increases the stimulated emission lifetime demonstrating that it is not limited by Auger scattering, as widely believed, but by photoabsorption processes, involving defect states.