Fundamental physics of infrared detector materials

The fundamental parameters of IR photon detection are discussed relevant to the meaningful comparison of a wide range of proposed IR detecting materials systems. The thermal generation rate of the IR material is seen to be the key parameter that enables this comparison. The simple materials physics of 1) intrinsic direct bandgap semiconductors; 2) extrinsic semiconductors; 3) quantum well devices, including types I, II, and III superlattices; 4) Si Schottky barriers; and 5) high temperature superconductors, will be examined with regard to the potential performance of these materials as IR detectors, utilizing the thermal generation rate as a differentiator. The possibility of room temperature photon detection over the whole IR spectral range is discussed, and comparisons made with uncooled thermal detection.