Infrared detectors: status and trends

At present efforts in infrared detector research are directed towards improving the performance of single element devices, large electronically scanned arrays and higher operating temperature. Another important aim is to make IR detectors cheaper and more convenient to use. All these aspects are discussed in this paper. Investigations of the performance of infrared thermal detectors as compared to photon detectors are presented. Due to fundamental different types of noise, these two classes of detectors have different dependencies of detectivities on wavelength and temperature. Next, an overview of focal plane array architecture is given with emphasise on monolithic and hybrid structures. The objective of the next sections is to present the status of different types of detectors: HgCdTe photodiodes, Schottky-barrier photoemissive devices, silicon and germanium detectors, InSb photodiodes, alternative to HgCdTe III-V and II-VI ternary alloy detectors, monolithic lead chalcogenide photodiodes, quantum well and quantum dot infrared photodetectors. Final part of the paper is devoted to uncooled two-dimensional arrays of thermal detectors. Three most important detection mechanisms, namely, resistive bolometer, pyroelectric detectors and termopile are considered. The development of outstanding technical achievements in uncooled thermal imaging is also presented.