Abstract
Infrared (IR) detectors operated in the space environment are required to have high performance while being subjected to
a variety of radiation effects. Sources of radiation in space include the trapped particles in the Van Allen belts and
transient events such as solar events and galactic cosmic rays. Mercury cadmium telluride (MCT)-based IR detectors
are often used in space applications because they have high performance and are generally relatively tolerant of the space
environment when passivated with CdTe; often, the readout-integrated circuit is far more susceptible to radiation effects
than the detector materials themselves. However, inherent manufacturing issues with the growth of MCT have led to
interest in alternative detector technologies including type-II strained-layer superlattice (T2SLS) infrared detectors with
unipolar barriers. Much less is known about the radiation tolerance properties of these SLS-based detectors compared to
MCT. Here, the effects of 63 MeV protons on variable area, single element, dual-band InAs/GaSb SLS detectors in the
pBp architecture are considered. When semiconductors devices are irradiated with protons with energies of 63 MeV the
protons are capable of displacing atoms within their crystalline lattice. The SLS detectors tested here utilize a pBp
architecture, which takes advantage of the higher mobility electrons as the minority photocarrier. These detectors are
also dual-band, implying two absorbing regions are present and separated by the unipolar barrier. The absorbers have
cutoff wavelengths of roughly 5 and 9 μm allowing for mid-wave (MWIR) and long-wave (LWIR) infrared detection,
respectively. The radiation effects on these detectors are characterized by dark current and quantum efficiency as a
function of total ionizing dose (TID) or, equivalently, the incident proton fluence.
