Design and Simulation of Avalanche Photodetectors Based on InAs/GaSb Superlattices

This paper demonstrates the design, modeling, and simulation of an optimized avalanche photodetectors (APDs) based on InAs/GaSb superlattice structures for midwave infrared (MWIR) applications. The proposed detector architecture incorporates spatially separated regions for absorption, grading, charge control, and carrier multiplication (SAGCM configuration), leveraging the broken-gap band structure of InAs/GaSb superlattices yielding superior quantum efficiency and reduced dark current relative to traditional mercury cadmium telluride (MCT) devices. Besides, we demonstrate multiplication gains greater than 100 with a noise equivalent power (NEP) below $10^{-15} ~\mathrm{W} / \sqrt{ } \text{Hz}$ at 77 K by a thorough device simulation. High impact ionization efficiency and low tunneling currents are obtained by optimizing the superlattice structure with specific layer thicknesses and doping profiles. According to the results, InAs/GaSb superlattice APDs could be an excellent choice for next-generation infrared detection systems and offer promising alternatives to conventional MCT detectors with improved manufacturability and radiation hardness compared to present technologies.