Spin dynamics of the neutral and charged InP self-assembled quantum dots

We have studied the kinetics of the polarized photoluminescence of the InP quantum dots in the magnetic field as a function of their charge state. In zero magnetic field, the degree of circular polarization of electrically neutral quantum dots rapidly decays with time constant about 13 ps. In longitudinal magnetic field, a slow component appears in the kinetics of degree of the circular polarization. Decay time of the slow component is about 300 ps. In the kinetics of the negatively charged quantum dots we have found a long-lived component of the degree of circular polarization, showing practically no decay during the lifetime of excitation. Spin relaxation processes responsible for depolarization of photoluminescence are discussed.