Molecular beam epitaxy growth of high quantum efficiency InAs/GaSb superlattice detectors

InAs/GaSb superlattices are leading candidates for next generation long-wave infrared and very-long-wave infrared photodetectors. These heterostructures are expected to hold important advantages over existing materials systems, primarily bulk HgCdTe alloys. To realize their inherent potential, however, superlattice materials with low defect density and improved device characteristics must be demonstrated. Here, we report on the molecular beam epitaxy growth and characterization of an 11 μm cutoff wavelength InAs/GaSb superlattice detector with a state-of-the-art single-pass, internal quantum efficiency of 36%. The shutter sequencing used to form the GaSb-on-InAs and InAs-on-GaSb superlattice heterojunctions is described in detail, and the latter specifically identified as a source of morphological defects in these devices.