An examination of the collective results from recent experiments quantifying the performance degradation rates of III-V-based, unipolar barrier infrared detectors with various designs and materials, cutoff wavelengths and operating conditions due to 63 MeV proton irradiation is presented. Empirical relationships were established between the radiation damage factors for dark current density, lateral optical collection length, and quantum efficiency and the inverse product of the detectors' cutoff wavelength and operating temperature. Fitting the dark current density damage factor's empirical relationship reflected these detectors' tendency to remain diffusion-limited during irradiation, which was previously established using Arrhenius-analysis of the post-irradiation, temperature-dependent dark current measurements on each. Collectively, the results affirmed the performance degradation stemmed from a reduction of the minority carrier recombination lifetime via generation of additional defects by proton-induced displacement damage. For comparing detector's radiation-tolerance, the results indicated that damage factors alone were not ideal, but their empirical relationships would serve as heuristics in this role.Index Terms-Damage factor, infrared detector, minority carrier lifetime, nBn, proton irradiation, unipolar barrier detector.

Midwave infrared (MWIR) photodetectors that do not require cryogenic cooling would significantly reduce the complexity of the cooling system, which would lead to a reduction in the size, weight, and cost of the detection system. The key aspect to realize high operating temperature (HOT) photodetectors is to design device structures that exhibit significantly lower levels of dark current compared to the existing technologies. One of the most attractive material systems to develop HOT photodetectors is InAs/GaSb Type II Strained layer Superlattice (SLS). This is due the ability of Type II SLS materials to engineer the band structure of the device, which can be exploited to make devices with unipolar barriers. It has been shown that, compared to the traditional homojunction SLS devices, band-gap engineered unipolar barrier SLS devices can obtain significantly lower levels of dark current. In this work, we report on the design, growth, and fabrication of mid wave infrared detectors based on type-II InAs/GaSb strained layer superlattice for high operating temperatures. The device architecture is the double-barrier heterostructure, pBiBn design. Under an applied bias of -10 mV and an operating temperature of 200 K, the tested devices show a dark current density of 4 x 10 -3 A/cm 2 and a quantum efficiency of 27%. At 4.5 μm and 200 K, the devices show a zero-bias specific detectivity of 4.4 x 10 10 Jones.

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