Method of electron affinity evaluation for the type-2 InAs/InAs_1−xSb_x superlattice

The type-2 InAs/InAs_1−xSb_x superlattices on GaAs substrate with GaSb buffer layer were investigated by comparison of theoretical simulations and experimental data. The algorithm for selection of input parameters (binary and ternary materials) for simulations is presented. We proposed the method of the bandgap energy extraction of the absorption curve. The correct choice of the bulk materials and bowing parameters for the ternary alloys allows to reach good agreement of the experimental data and theoretical approach. One of the key achievements of this work was an electron affinity assessment for the device's theoretical simulation. The detectivity of the long-/very long-wave InAs/InAs_1−xSb_x superlattice photoconductors at the level of ~ 8 × 10⁹ cm Hz^1/2/W (cutoff wavelength 12 µm) and ~ 9 × 10⁸ cm Hz^1/2/W (cutoff wavelength 18 µm) at a temperature 230 K confirmed the good quality of these materials.