XBn and XBp barrier detectors offer diffusion limited dark currents and high operating temperatures. Type II superlattices (T2SLs) based on either InAs/GaSb or InAs/InAsSb are ideal for their fabrication for two important reasons. First, their band gaps can be matched to the mid-wave infrared (MWIR) or long-wave infrared (LWIR) transparency ranges of the atmosphere, and second, their mini-band edges can be designed to create a large barrier for majority carriers and a negligible barrier for minority carriers, two requirements necessary for successful device operation. The main challenges are a short lifetime for both types of minority carrier in InAs/GaSb T2SLs, and non-metallic hole conductivity in both types of T2SL leading to a very low hole mobility. In this work we demonstrate how these challenges can be met, by exploiting very high electron mobilities in InAs/GaSb T2SLs, and a long Auger limited hole-lifetime in the gallium free T2SL for doping levels below 1015 cm-3. Full MWIR focal plane array (FPA) operating temperatures are presented close to 130K, and robust LWIR FPA operation is demonstrated at 77K.
