Extended Short-Wave Infrared Barrier Structure Focal Plane Array Based on InGaAs/GaAsSb Type-II Superlattices

We present a extended short-wave infrared photodetector featuring a p-doped InGaAs/GaAsSb type-II superlattices (T2SL) absorber encapsulated by a pair of electron-blocking and hole-blocking barriers. Each barrier uses different InGaAs/GaAsSb T2SL design lattice matched to InP substrate. The single element device exhibits 100% cut off wavelength of 2.32 μm at 300 K. It achieves saturated QE values of 50.7% at 1.6 μm under front-side illumination without any anti-reflection coating. At 300 K, the photodetector exhibits a dark current density of 5.38 × 10⁻³ A/cm² under −20 mV applied bias, providing a specific detectivity of 8.18 × 10⁹ Jones. Clear infrared imaging using f/2 optics and an integration time of 12 ms was obtained at 300 K by a 640 × 512 focal plane array using the same structure design.