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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.

Time-resolved photoluminescence measurements reveal a minority carrier lifetime of >412 ns at 77 K under low excitation for a long-wavelength infrared InAs/InAs0.72Sb0.28 type-II superlattice (T2SL). This lifetime represents an order-of-magnitude increase in the minority carrier lifetime over previously reported lifetimes in long-wavelength infrared InAs/Ga1−xInxSb T2SLs. The considerably longer lifetime is attributed to a reduction of non-radiative recombination centers with the removal of Ga from the superlattice structure. This lifetime improvement may enable background limited T2SL long-wavelength infrared photodetectors at higher operating temperatures.

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