DIRECT MEASUREMENT OF THE RECOMBINATION RATES IN BULK INSB BY TIME-RESOLVED PHOTOLUMINESCENCE

Time-resolved photoluminescence has been used to study the decay of photoexcited carriers in bulk InSb at 2 K. The recombination occurs as a two step process exhibiting a fast and a slow decay. The fast decay, corresponding to band-to-band recombination, occurs with a time constant of the order of 60 nsec and is accompanied by time-resolved band gap renormalization. The slow process, identified in the band-to-acceptor photoluminescence, occurs with a time constant of 3.8-mu-sec. We show that this is in excellent agreement with the theoretical value of the band-to-acceptor radiative transition rate. These results help reconcile discrepancies that have long existed between conventional photoluminescence measurements and time-resolved photoconductivity measurements.