Phonon-assisted biexciton generation in a single quantum dot

Phonon-assisted absorption of a single InGaAs/GaAs quantum dot is investigated by multichannel photoluminescence excitation spectroscopy as a function of magnetic field. GaAs LO phonon-assisted generation of exciton and biexciton states is observed. Magnetic field induced detuning of the resonance conditions results in a twofold diagonal splitting of the exciton and a symmetric fourfold splitting of the biexciton resonances. Those findings are explained in terms of sequential phonon-assisted biexciton generation followed by sequential biexciton decay.