Mid-IR focal plane array based on type-II InAs/GaSb strain layer superlattice detector with nBn design

A midwave infrared camera (lambda(c)=4.2 mu m) with a 320 x 256 focal plane array (FPA) based on type-II InAs/GaSb strain layer superlattice (SLs) has been demonstrated. The detectors consist of an nBn heterostructure, wherein the SL absorber and contact layers are separated by a Al0.2Ga0.8Sb barrier layer, which is designed to have a minimum valence band offset. Unlike a PN junction, the size of the device is not defined by a mesa etch but confined by the lateral diffusion length of minority carriers. At 77 K, the FPA demonstrates a temporal noise equivalent temperature difference (NETD) of 23.8 mK (T-int=16.3 ms and V-b=0.7 V) with a peak quantum efficiency and detectivity at 3.8 mu m equal to 52% and 6.7 x 10(11) Jones, respectively. (C) 2008 American Institute of Physics.