The modeling of a SWIR type-II InAs/AlSb superlattice using an ETBM and interface engineering

Abstract

A short-wavelength infrared InAs/AlSb type-II superlattice photodetector has been modeled with 15 Mono Layer (ML) of InAs and 4 Mono Layer (ML) of AlSb. In this work, the Empirical Tight-Binding Method (ETBM) was used to calculate the band structure and predict the material of the interfaces. In addition, the effective mass of the heavy hole, light hole, and electron was calculated for each type of the interfaces by tight binding s p 3 s ∗ modeling. Based on the results, the material of the interfaces plays a critical role in lattice mismatch and cutoff wavelength. The detector cutoff wavelength can be changed by atomic engineering of the superlattice interfaces and changing the thicknesses of InAs and AlSb. The simulation results are in good agreement with the experimental values and prove that the [ ( I n A s ) 15 − I n S b − ( A l S b ) 4 − A l A s ] is the most suitable structure. In order to match the simulation results with experimental results, the effect of the segregation on the band structure was evaluated. In this case, the cutoff wavelength of the SWIR detector is 3.27 μ m and the lattice mismatch between the superlattice and the GaSb (100) substrate is 0.63%. • A SWIR InAs/AlSb T2SL photodetector has been modeled with 15 ML of InAs and 4 ML of AlSb. • (ETBM) is used to calculate and predict the material of the interfaces. • The effective mass of the heavy hole, light hole, and electron was calculated for each type of the interfaces by tight binding s p 3 s ∗ modeling. • The flowchart of extracting the band structure by ETBM is presented. • The migration of atoms in interfaces is investigated.