Increased Lifetime and Decreased Dark Current in Ga-Free Long Wave Infrared (LWIR) T2SL through Defect Identification and Mitigation

Absorber layers based on Type-II superlattices (T2SLs) composed of III-V compound semiconductors (e.g. InAs and InSb) are a promising sensor technology for infrared imaging; however, quantum efficiencies from as-grown T2SL material often falls short of the design target, particularly in high-Sb, LWIR T2SL designs that should provide high absorption efficiency.There is strong evidence that these shortfalls result due to deviation of the structure and chemical composition between the grown T2SL and its design.Molecular dynamics-based molecular beam epitaxy growth simulations will be used to evaluate T2SL design and growth strategies that minimize this deviation.The most promising strategies identified from the simulation results will be validated by experiments that will assess the theoretical understanding and optimize a growth process based on the predictions. Technology transfer to commercial T2SL material foundries will also take place.