There is currently considerable interest in InAs/GaSbtype-II superlattices because of their tunable bandgap in the range of 3-30 µm and the potential for thenext generation mid-infrared photodetector focalplane arrays. In order to understand the underlyingphysics of this emerging technology, this bookprovides both theoretical and experimental studies onthis subject. An eight-band k-p method is introducedto model the band structures and absorptioncoefficient of this material. Quantum efficiency, animportant figure of merit for infraredphotodetectors, is also analyzed by an analyticalmodel based on absorption coefficient and transportparameters. Understanding the dark current mechanismsof InAs/GaSb superlattice photodiodes is anotherimportant task where the surface leakage current isdetrimental. We provide a comprehensive model toexplain the experimentally measured current-voltagecurves to help readers understand the underlyingdark current mechanisms. Besides conventionalphotodiodes, we show examples of more sophisticateddesigns with the help of quantum engineering based onthe eight-band k-p method to explore novel devicestructures.