High performance photodiodes based on InAs/InAsSb type-II superlattices for very long wavelength infrared detection

Very long wavelength infrared photodetectors based on InAs/InAsSb type-II superlattices are demonstrated on GaSb substrate. A heterostructure photodiode was grown with 50% cut-off wavelength of 14.6 mu m. At 77 K, the photodiode exhibited a peak responsivity of 4.8 A/W, corresponding to a quantum efficiency of 46% at -300mV bias voltage from front side illumination without antireflective coating. With the dark current density of 0.7 A/cm(2), it provided a specific detectivity of 1.4 x 10(10) Jones. The device performance was investigated as a function of operating temperature, revealing a very stable optical response and a background limited performance below 50K. (C) 2014 AIP Publishing LLC.