Type-II superlattice detector for long-wave infrared imaging

Abstract

When incorporated into the active layer of a "XB<i>p</i>" detector structure, Type II InAs/GaSb superlattices (T2SLs) offer a high quantum efficiency (QE) and a low diffusion limited dark current, close to MCT Rule 07. Using a simulation tool that was developed to predict the QE as a function of the T2SL period dimensions and active layer stack thickness, we have designed and fabricated a new focal plane array (FPA) T2SL XB<i>p</i> detector. The detector goes by the name of "Pelican-D LW", and has a format of 640 &times;512 pixels with a pitch of 15 &mu;m. The FPA has a QE of 50% (one pass), a cut-off of ~9.5 &mu;m, and operates at 77K with a high operability, background limited performance and good stability. It uses a new digital read-out integrated circuit, and the integrated detector cooler assembly (IDCA) closely follows the configuration of SCD’s Pelican-D MWIR detector.