Spin Lifetime in Electron-Doped InP Quantum Dots
  Spin relaxation of electrons doped in InP quantum dots was studied by means of luminescence pump-probe and Hanle measurements. Optical pumping makes spins of doped electrons to be oriented in parallel to the helicity of the circularly polarized excitation. The luminescence pump-probe showed the spin orientation of the doped electrons decay on a millisecond time-scale. Hanle measurement clarified the spin dephasing relaxation time of doped electrons is 1.7 ns which is explained by the frozen fluctuation of nuclear spins. 
Y. Masumoto, B. Pal, S. Oguchi, M. Ikezawa