Infrared Detectors - New Trends

Recent trends in infrared detectors are towards large, electronically addressed two-dimensional arrays and higher operating temperature. This will lead both to higher performance and to smaller, lighter and more affordable IR systems. Cooling requirements are the main obstacle to the more widespread use of infrared systems based on semiconductor photodetectors, particularly in the civil field. Fundamental limitations to performance of IR photodetectors are due to the statistical nature of generation-recombination processes and resulting noise. Ways to overcome the limitations are discussed including use of the optical immersion and optical resonant cavity. Finally, the progress in a mode of operation is presented, in which the thermal generation of carriers is suppressed by the use of stationary depletion of narrow gap semiconductors. The practical near room temperature narrow gap semiconductor photodetectors are reported. Competitive technologies based on Schottky barrier devices and low dimensional solids are considered briefly