Minority carrier lifetime of strain-balanced InGaAs/InAsSb superlattices and associated detector performance gains in mid-wave infrared space applications

Being the ultimate high ground, space-based surveillance has long been a critical aspect of every
nation’s defense strategy. In the years to come, development of manufacturable, high-yield detector
materials tolerant of the space radiation environment will be critically important to outfit increasingly
larger constellations of infrared surveillance satellites. In one material solution discussed here, strain-
balanced InAs/InAsSb superlattices already in use today can be significantly improved by the inclusion of
Ga in an InGaAs/InAsSb superlattice. In this system, converting InAs to more heavily-strained InGaAs
produces a more symmetric strain-balance condition leading to stronger hole wavefunction coupling
that serves to improve hole mobility and absorption that limit performance in Ga-free InAs/InAsSb.
These materials have recently been demonstrated with long minority carrier lifetimes comparable to
their Ga-free counterparts, eliminating a technological problem that has until now severely limited their
utility. Recent material quality advances, infrared detector performance, and radiation damage testing
will be discussed at the conference.