Auger recombination and state filling of resonantly excited ground state in CdSe quantum dots

Dynamics and state filling of the resonantly excited ground state (1s(e)-1S(3/2)(h)) in a strongly confined CdSe quantum dot were investigated by degenerate pump-probe measurements. With increasing the electron-hole (e-h) pairs per dot the state filling and bleaching were observed with similar to 2.7 e-h pairs. While radiative recombination was dominant with a small number of the e-h pairs (< 1), the Auger-type recombination became significant near the bleaching number of e-h pairs (similar to 2.7). This result suggests that, for resonant excitation, either cold electron or hole of the ground state is scattered into the higher-energy states of a ZnS shell via Auger recombination process (similar to 28 ps). (c) 2007 American Institute of Physics.