Theoretical Design Of InAs/InAsSb Type ? Superlattice Infrared Detection Materials

The Sb-based type ? superlattice has good growth quality,flexible and precise adjustable bandgap,excellent optical performance,and has broad development prospects in the field of infrared detection.The Ga-free InAs/InAsSb type ? superlattices have longer minority carrier lifetime compared to InAs/Ga?In?Sb,have gained much attention experimentally in recent years,and have great tendency to become the preferred material for infrared detectors.In the theoretical description of the type ? superlattice,the traditional kp perturbation theory and the envelope function approximation are easily controversial because of the non-universality of the low momentum assumption and the non-deterministic nature of the envelope function at the interface.The all-atom empirical pseudopotential method can effectively avoid the above errors and has become a powerful tool to solve the electronic structure of large-scale systems.In this paper,the all-atom empirical pseudopotential method is used to investigate the effect of different growth modes on the band-edge energy levels of InAsSb alloy system.An experimentally advanced type ? superlattice structure 173 A InAs/72 A InAs_0.72Sb_0.28 is a blueprint for the superiority of the structure compared with related materials and the type I superlattice from the viewpoint of the local and transitional matrix elements in the carrier space.The influence of the composition and thickness of the alloy layer on the band-edge energy level of the superlattice was explored,and the importance of the quantum confinement effect was confirmed;and the band-edge transition matrix element was used as a quality factor to measure carrier lifetime for the fixed band.The superlattice system was optimized to obtain a better performance system 163 A InAs/82 A InAs_0.72Sb_0.28.