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Single photon emission is investigated for fast radiative quantum dots. A simple model including capture process shows that the probability that a second photon is emitted increases when decreasing the exciton radiative lifetime. This effect is experimentally demonstrated through photon correlation measurements on single GaAs quantum dots presenting various radiative lifetime. The same model is used to estimate the second order autocorrelation function for an InAs quantum dot experiencing strong Purcell effect. The calculation shows the limitations of using Purcell effect to realize efficient single photon sources. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

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.

We report on photoluminescence on single GaAs 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, that appears whenever the biexciton is observed. A simple model allows us to account for our observations and to show that this sideband is the spectral signature of ultra fast quantum dots in continuous wave measurements.

Photon correlation measurements are performed on single GaAs quantum dots with various excitonic radiative lifetimes. A continuous increase of the probability that the quantum dot emits more than one photon per excitation pulse is observed when decreasing the exciton radiative lifetime. The authors show that this increase is due to recapture processes into the quantum dot. A model for the second-order autocorrelation function including relaxation processes is developed and gives good description of the experimental observations.

We report on time resolved measurements on single monolayer fluctuation GaAs quantum dots. We measure radiative lifetimes as short as 100 ps for the exciton. Studying various single quantum dots, we demonstrate that the radiative lifetime of the exciton is controlled by the quantum dot lateral size.