Mou, S: InAs/GaSb Type-II Superlattices

There is currently considerable interest in InAs/GaSb type-II superlattices because of their tunable band gap in the range of 3 30 m and the potential for the next generation mid-infrared photodetector focal plane arrays. In order to understand the underlying physics of this emerging technology, this book provides both theoretical and experimental studies on this subject. An eight-band k p method is introduced to model the band structures and absorption coefficient of this material. Quantum efficiency, an important figure of merit for infrared photodetectors, is also analyzed by an analytical model based on absorption coefficient and transport parameters. Understanding the dark current mechanisms of InAs/GaSb superlattice photodiodes is another important task where the surface leakage current is detrimental. We provide a comprehensive model to explain the experimentally measured current-voltage curves to help readers understand the underlying dark current mechanisms. Besides conventional photodiodes, we show examples of more sophisticated s with the help of quantum engineering based on the eight-band k p method to explore novel device structures.