Simulation model of the performance of a mid-wave infrared Ga-free type 2 superlattice barrier photodetector

A numerical model has been developed to simulate mid-wave infrared Ga-free InAs/InAsSb type 2 superlattice (T2SL) unipolar barrier (XBn) technology-based photodetectors. The model has been extensively studied to evaluate the effects of doping levels and the thickness of both the absorber and barrier layers on key metrics such as dark current (DC) and quantum efficiency (QE). The model utilizes the nextnano 8-band k·p theory and optics module to solve the Schrödinger equation and compute the band dispersion and the absorption coefficient. The band dispersion of the structure demonstrates the formation of minibands, indicating the carrier’s delocalization. This crucial condition allows us to consider the T2SL as a bulk material. Material parameters such as band gap energy, electron and hole effective masses, intrinsic concentration, and extinction coefficient are extracted from the quantum simulation results and input into the Technology Computer-Aided Design software by Silvaco. The software solves the Poisson drift–diffusion continuity equations to compute the DC and QE. The model has been validated using experimental results from existing literature, demonstrating good agreement with experimental findings, making it an effective tool for designing and predicting the performance of Ga-free T2SL XBn technology-based structures.