Design And Growth Of Short-Period Long Wavelength Infrared Inassb/Inassb Superlattices On Lattice Engineered Metamorphic Buffers

There has been steady effort to advance Ga-free InAs1-xSbx/InAs1-ySby superlattice (SL) materials for long-wavelength infrared (LWIR) detector applications. Although Ga-free SLs grown pseudomorphically on GaSb wafers work well in mid-wavelength applications, most LWIR Ga-free SL designs suffer from relatively low optical absorption and poor hole transport. One of the main problems in using the Ga-free material system for LWIR applications is a tremendous constraint on band engineering imposed by matching the SL lattice parameter to the lattice constant of conventional GaSb substrates. In this work, we propose several lattice engineered short-period LWIR InAs1-xSbx/InAs1-ySby SL designs that can enhance optical absorption and vertical hole mobility at an 11 mu m cutoff wavelength. We also performed test growths of the designed structures on lattice-matched homogeneous buffer layers on GaAs wafers.