Design of electron and hole barriers for type-II superlattice absorber for infrared photodetection

For the construction of the absorber region in infrared photodetectors, type-II Superlattice is favored over traditional HgCdTe due to its band-tunability. The generation recombination processes that result in noise-inducing currents in these infrared detectors are a significant performance bottleneck, so over the past few years, there have been a lot of research efforts aimed at mitigating these processes to ensure high-temperature operation with improved figure-of-merits. In this work, we showcase the electron and hole barriers for type-II superlattice absorbers to reduce these prime dark current components in infrared photodetectors. Here, we investigate the electronic band properties of InAs/AlSb, GaSb/AlSb, and M-superlattice (InAS/GaSb/AlSb/GaSb) materials as carrier-impending barriers by employing the 8 band k.p method and the non-equilibrium green's function approach. In this article, we demonstrate that InAs/AlSb (GaSb/AlSb) only ever function as a hole (electron) barrier and never as an electron (hole) barrier. Additionally, we show that we can achieve both the electron and hole barriers by modifying the material widths in the M-superlattice.