Background–limited long wavelength infrared InAs/InAs1− xSbx type-II superlattice-based photodetectors operating at 110 K

We report the demonstration of high-performance long-wavelength infrared (LWIR) nBn photodetectors based on InAs/InAs1− xSbx type-II superlattices. A new saw-tooth superlattice design was used to implement the electron barrier of the photodetectors. The device exhibited a cut-off wavelength of ∼10 μm at 77 K. The photodetector exhibited a peak responsivity of 2.65 A/W, corresponding to a quantum efficiency of 43%. With an R × A of 664 Ω·cm2 and a dark current density of 8 × 10−5 A/cm2, under −80 mV bias voltage at 77 K, the photodetector exhibited a specific detectivity of 4.72 × 1011 cm·Hz/W and a background–limited operating temperature of 110 K.