Internal quantum efficiency in 6.1 Å superlattices of 77% for mid-wave infrared emitters

Two new superlattices with high internal quantum efficiency at high injection, InAs/AlGaInSb and InAs/GaInSb/InAs/AlAsSb, are presented and compared with state-of-the-art InAs/GaSb and InAs/InAsSb superlattices. The internal quantum efficiency peaks at 44% and 77% for the InAs/AlGaInSb and InAs/GaInSb/InAs/AlAsSb samples, respectively, which suggests that they are excellent candidates for high-efficiency mid-wave infrared LEDs. These values have been measured without invoking the ABC model to eliminate the assumption of Boltzmann statistics. The calculated superlattice band structures are used qualitatively to explain the internal quantum efficiency results.