High operating temperature pBn barrier mid-wavelength infrared photodetectors and focal plane array based on InAs/InAsSb strained layer superlattices

Improving the operation temperature of the focal plane array (FPA) imagers is critical in meeting the demands to reduce the size, weight, and power (SWaP) for mid-infrared detection systems. In this work, we report the demonstration of a 15 µm-pitch 640×512 middle-format pBn FPA device with a 50% cutoff wavelength of 4.8 µm based on short period of InAs/InAsSb-based "Ga-free" type-II strained-layer superlattices, which achieves a high operating temperature (HOT) reaching 185 K. The pBn FPA exhibits a mean noise equivalent differential temperature (NETD) of 39.5 mK and an operability of 99.6% by using f/2.0 optics for a 300 K background at 150 K. The mean quantum efficiency is 57.6% without antireflection coating and dark current density is 5.39×10-5 A/cm2 at an operation bias of -400 mV, by which the mean specific detectivity(D*) is calculated as high as 4.43×1011 cm.Hz½/W.