High resistance narrow band quantum cascade photodetectors

A high resistance narrow band quantum cascade photodetector (QCD) is presented. Leakage current has been suppressed, increasing the resistivity, thanks to a design in which coupling barriers have been thickened. Useless cross transitions have been eliminated finally leading to a Johnson noise detectivity at 50 K comparable to quantum well infrared photodetectors. Because they work with no dark current, QCDs are very promising for small pixel and large focal plane array applications. (C) 2005 American Institute of Physics.