Flexible Band Gap Engineering of Ternary-Based InAs/AlAs1−xSbx/InAs1−xSbx Superlattice

This study demonstrates an overall view of recent modeling efforts using quantum mechanical-based empirical tight-binding methods to calculate the electronic band structure for strained-layer superlattices composed of ternary InAs/InAs1−xSbx and InAs/InAs1−xSbx/AlAs1−xSbx materials. By employing a modified sp3s* empirical tight-binding method, we show that integrating the virtual crystal approximation with a bowing parameter for the s-on-site energy successfully predicts ternary superlattice behavior. We present an overall view of our findings from numerical simulations to model various superlattice designs, from a narrow bandgap design to wide-bandgap barrier architectures. A narrow-band mid-wavelength infrared design with a 260 meV bandgap (~5 μm cut-off) and a wide-bandgap short-wavelength infrared architecture with a high bandgap of 701.1 meV (~1.9 μm cut-off) were simulated. These simulated energy bandgaps show strong agreement with experimental bandgap measurements of the same design of grown ternary superlattice material.