Abstract. This work sununanzes recent data on minority carrier lifetime in n-and p-type double heterostructures (DHs) of 0.5-0.6 eV GalnAsSb confined with GaSb and AIGaAsSb cap layers. Recombination times were measured by time-resolved photoluminescence (TRPL) and by optical frequency response (OFR) to sinusoidal excitation. It was shown that one of the mechanisms responsible for interface recombination in GaSb/GalnAsSb/GaSb DHs is thermionic emission of carriers over the heterobarrier. Considerable improvement of carrier confinement was obtained with I eV AIGaAsSb cap layers. Optimization of the epitaxial growth resulted in a recombination velocity at GalnAsSb/ AIGaAsSb interface as low as 30 crn/s.

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