By using polarization-resolved photoluminescence spectra, we study the electron spin
relaxation in single InAs quantum dots (QDs) with the configuration of positively charged
excitons X+(one electron, two holes). The spin relaxation rate of the hot electrons increases
with the increasing energy of exciting photons. For electrons localized in QDs the spin
relaxation is induced by hyperfine interaction with the nuclei. A rapid decrease of
polarization degree with increasing temperature suggests that the spin relaxation …