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We report design, growth, and characterization of midwavelength infrared nBn photodetectors based on a type-II InAs/InAs1-xSbx superlattice on a GaSb substrate grown by metal-organic chemical vapor deposition. An InAs/AlAs1-ySby/InAs/InAs1-xSbx superlattice design was used as the large bandgap electron barrier in the photodetectors. At 150 K, the photodetector exhibits a peak responsivity of 1.23 A/W, corresponding to a quantum efficiency of 41% at an applied bias voltage of −100 mV under front-side illumination, with a 50% cut-off wavelength of 4.6 μm. With an R × A of 356 Ω cm2 and a dark current density of 1.6 × 10−4 A/cm2 under an applied bias of −100 mV at 150 K, the photodetector exhibits a specific detectivity of 1.4 × 1011 cm Hz1/2/W. [ABSTRACT FROM AUTHOR]

We report the growth and characterization of mid-wavelength infrared type-II InAs/InAs1−xSbx superlattice photodiodes on GaSb substrates grown by metal-organic chemical vapor deposition. At 150 K, the 50% cut-off wavelength is 5.0 μm, the dark current density is 3.3 × 10−4 A/cm2 under −20 mV bias, and the peak responsivity is 1.76 A/W corresponding to a quantum efficiency of 55% without anti-reflection coating. A specific detectivity of 1.2 × 1011 cm Hz1/2/W is achieved at 4.0 μm under −20 mV bias at 150 K. [ABSTRACT FROM AUTHOR]