Optical spectroscopy of single trions

Summary form only given. We observed distinctive signatures in the magneto-optical fine structure spectra of singly charged and uncharged QDs. We show that in the absence of a magnetic field the photoluminescence spectrum is characterized by two predominant transitions that we identify as exciton and trion singlet recombination transitions. As the temperature is increased several lines rapidly decrease in intensity. By 30 K all lines related to the trion disappear. This effect is due to the ionization of one of the electrons from the three-particle trion system.