Exciton dynamics in the presence of an electron gas in GaAs quantum wells

The dynamics of excitons in a GaAs quantum well in the presence of an electron gas is investigated by time resolved photoluminescence (PL). We prove that the emission at the exciton energy originates from a real exciton population for all time delays. Moreover we show that injecting a low density electron gas strongly accelerates the exciton dynamics, by increasing the exciton formation rate.