ORIGIN OF PHOTOLUMINESCENCE SIGNALS OBTAINED BY PICOSECOND-EXCITATIONCORRELATION-MEASUREMENTS

We have developed a theory that explains the spectral distribution and the different time decay behaviors of the signals observed in picosec ond excitation-correlation measurements of semiconductor materials. Th e results display good quantitative agreement with experiments on mult iple quantum wells and show that band filling has an important role in determining the characteristics of the correlation signals. Two limit cases are found and mathematically characterized: the non-degenerate regime, where the signals are positive with exponential-like decays, a nd the degenerate regime, where band filling gives rise to negative si gnals. It is shown that the technique is a sensitive probe of the carr ier dynamics not fully exploited in previous work.