Type-II Superlattices for Infrared Detection: Diffusion Characterization Using Electron Beam Induced Current

Abstract

Type-II superlattices (T2SLs) primarily utilizing antimonide-based III-V materials have been the subject of significant interest for their mid-wave or long-wave infrared (MWIR or LWIR) detection capabilities. The continuing development of these detector structures depends on the ability to accurately measure the minority carrier lifetimes and diffusion characteristics of the T2SL material. Our nBn detector samples were fabricated via a standard photolithography and chemical wet etch into square mesas with top and bottom contacts using Ti/Pt/Au. This thesis introduces a scanning electron microscope-electron beam induced current (SEM-EBIC) technique to study defects in our fabricated devices. By comparing experimental data to the simulated results, a sample's surface recombination velocity and its minority carrier diffusion length can be extracted.