Measurements of carrier recombination rates using a time-resolved pump-probe technique are reported for mid-wave infrared InAs/InAs1−xSbx type-2 superlattices (T2SLs). By engineering the layer widths and alloy compositions, a 16 K band-gap of ≃235 ± 10 meV was achieved for all five unintentionally doped T2SLs. Carrier lifetimes were determined by fitting a rate equation model to the density dependent data. Minority carrier lifetimes as long as 10 μs were measured. On the other hand, the Auger rates for all the InAs/InAsSb T2SLs were significantly larger than those previously measured for InAs/GaSb T2SLs. The minority carrier and Auger lifetimes were observed to generally increase with increasing antimony content and decreasing layer thickness.

Temperature-dependent measurements of carrier recombination rates using a time-resolved optical pump-probe technique are reported for mid-wave infrared InAs/InAs 1Àx Sb x type-2 superlattices (T2SLs). By engineering the layer widths and alloy compositions, a 16 K band-gap of $235 6 10 meV was achieved for five unintentionally and four intentionally doped T2SLs. Carrier lifetimes were determined by fitting lifetime models based on Shockley-Read-Hall (SRH), radiative, and Auger recombination processes to the temperature and excess carrier density dependent data. The minority carrier (MC), radiative, and Auger lifetimes were observed to generally increase with increasing antimony content and decreasing layer thickness for the unintentionally doped T2SLs. The MC lifetime is limited by SRH processes at temperatures below 200 K in the unintentionally doped T2SLs. The extracted SRH defect energy levels were found to be near mid-bandgap. Also, it is observed that the MC lifetime is limited by Auger recombination in the intentionally doped T2SLs with doping levels greater than n $ 10 16 cm À3. V

A high-performance InGaAs/GaAs vertical quantum dot infrared photodetector (QDIP) with combined barrier of quaternary In 0.21 Al 0.21 Ga 0.58 As and GaAs was investigated in this study. A dominant long wavelength ($10.2 lm) response was observed from the device. The device demonstrates large responsivity (2.16 A/W) with narrow spectral-width (Dk/k $0.14) and high detectivity (1.01 Â 10 11 cm Hz 1/2 /W at 0.3 V) at 10.2 lm at 77 K. In addition, the device has also produced a detectivity in the order of 6.4 Â 10 10 cm Hz 1/2 /W at 100 K at a bias of 0.2 V, indicating its suitability for high-temperature operations. V

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