Direct minority carrier lifetime measurements and recombination mechanisms in long-wave infrared type II superlattices using time-resolved photoluminescence

Abstract

We present a direct optical measurement of minority carrier lifetime as a function of temperature and excitation density in long-wave infrared InAs/GaSb type II superlattices using time-resolved photoluminescence. Results indicate that carrier lifetime is dominated by Shockley–Read–Hall recombination, with a lifetime of 30 ns at 77 K. Below 40 K, we observe a freeze-out of carriers and increased contributions from radiative recombination. High-injection measurements yield a radiative recombination coefficient of 1.8×10−10 cm3/s and an upper limit of the Auger recombination coefficient of 10−28 cm6/s at 60 K. An acceptor level of ∼20 meV above the valence band is also determined.