Strained and Unstrained Layer Superlattices for Infrared Detection

Strained HgTe/CdZnTe or InAs/GaInSb, and essentially unstrained HgTe/CdTe superlattices (SLs), are possible materials systems for implementation in future-generation infrared imaging systems. In addition to cutoff wavelengths spanning the infrared spectrum, they offer degrees of freedom in their design (e.g., layer thicknesses, alloy compositions, and number of layers in one superlattice period) that permit the optimization of an infrared detector’s figures of merit such as detectivity through the tuning of material properties such as recombination lifetimes and optical absorption. This paper provides a brief overview of the anticipated advantages of the SLs over HgCdTe alloy-based infrared photon detector technology and the relative merits of the II–VI and III–V semiconductor-based SLs.