LWIR SLS-based Linear Mode APD materials strain-balanced to large diameter GaSb substrate

This Phase I STTR proposes to develop high-quality high-performance infrared epitaxy materials based on strained layer superlattice absorber material and AlGaAsSb multiplication layer lattice matched to GaSb substrate for extended Long-Wave Infrared (LWIR) linear-mode avalanche photodiode (APD) applications such as improved target identification. The epi materials will be grown with Sb-capable multi-wafer production Molecular Beam Epitaxy (MBE) reactor at IntelliEPI IR. The initial goal includes achieving low excess noise and high multiplication (>10) operation within LWIR band with spectral cutoff wavelength of ~9 um and dark current density <10nA. In the Sb-based engineered structure, many device properties are determined once epitaxial growth is completed. The technical approach will be to develop improved epitaxial stack design and grown methodology with a goal to dramatically improved detector properties. This approach is based on existing high performance GaSb-based detector technology, with novel design, development of MBE growth to implement the design, and fabrication and characterization of devices from the epi grown material. The Phase II effort will focus on optimization and array demonstration.