Few particle effects in the emission of short-radiative-lifetime single quantum dots

We report on photoluminescence measurements on single GaAs monolayer fluctuation quantum dots. We show that, because the quantum dots have short radiative lifetime, the biexciton line is composed of various contributions originating from the Coulomb interaction with higher energy excitons. This appears as a broad low energy sideband on the biexciton line which appears for an average number of excitons in the system as small as 0.3. A simple model allows us to account for our observations and to show that this sideband is the spectral signature of fast quantum dots in continuous wave measurements.