Picosecond Nonlinear Relaxation of Photoinjected Carriers in a Single   GaAs/AlGaAs Quantum Dot
  Photoemission from a single self-organized GaAs/AlGaAs quantum dot (QD) is temporally resolved with picosecond time resolution. The emission spectra consisting of the multiexciton structures are observed to depend on the delay time and the excitation intensity. Quantitative agreement is found between the experimental data and the calculation based on a model which characterizes the successive relaxation of multiexcitons. Through the analysis we can determine the carrier relaxation time as a function of population of photoinjected carriers. Enhancement of the intra-dot carrier relaxation is demonstrated to be due to the carrier-carrier scattering inside a single QD. 
T. Kuroda, S. Sanguinetti, M. Gurioli, K. Watanabe, F. Minami, and N.   Koguchi