ABSTRACT
In 1959, Lawson and co-workers publication1 triggered development of variable band gap Hg^Cd^Te (HgCdTe) alloys providing an unprecedented degree of freedom in IR detector design. HgCdTe technology development was and con tinues to be primarily for military applications. A negative aspect of support of defence agencies has been the associated secrecy requirements that inhibit meaningful collaborations among research teams on a national and especially on an international level. In addition, the primary focus has been on FPA demon stration and much less on establishing the knowledge base. Nevertheless, sig nificant progress has been made over three decades. At present HgCdTe is the most widely used variable gap semiconductor for IR photodetectors. Over the years it has successfully fought off major challenges from extrinsic silicon and lead-tin telluride devices, but despite that it has more competitors today than ever before. These include Schottky barriers on silicon, SiGe heterojunctions, AlGaAs multiple quantum wells, GalnSb strain layer superlattices, high tem perature superconductors and especially two types of thermal detectors: pyro electric detectors and silicon bolometers. It is interesting, however, that none of these competitors can compete in terms of fundamental properties.2 They may promise to be more manufacturable, but never to provide higher performance or, with the exception of thermal detectors, to operate at higher or even comparable temperatures.
