4th generation infrared detectors and focal plane arrays

Abstract

Infrared imaging (3-25μm) has been an important technological tool for the past sixty years since the first report of infrared detectors in 1950s. The ability to detect the temperature of a scene from the blackbody radiation that it emits has spawned applications in a wide variety of fields ranging from defense and security to non-invasive medical diagnostics and remote sensing. However, IR imaging landscape has dramatically changed in the past decade. Firstly, the cost of lower end imagers has been steadily declining (30% every year since 2005) enabling them to be mounted on dashboards of automobiles including Audis and BMWs. Secondly, advent of novel antimonide based semiconductor technology has dramatically improved the performance of higher end imagers that are used for military, defense and security applications. There has been a dramatic progress in the development of infrared detectors in the past decade with new materials like InAsSb, InAs/GaSb superlattices and InAs/InAsSb superlattices. However, in spite of dramatic technological progress, there are a lot of unknowns in these materials. For instance, the background concentration, vertical mobility, diffusion constants etc for these systems are largely unknown or are very difficult to measure accurately. The GaSb conducting substrate coupled with anisotropic transport and quantum transport makes the investigating of this system challenging.