Very-Long-Wavelength Quantum Well Infrared Photodetector

Abstract

Abstract : Infrared detector is a very important part of infrared sensor technology. In ballistic missile defense, infrared sensors play an important role in missile seeking, tracking, guiding, discriminating, and intercepting. Tactical applications for endo-atmospheric situation are mostly under a high background (300K), where a high operating temperature above liquid nitrogen (77K) is desired. IR materials such as HgCdTe, InSb, PtSi and quantum well infrared photodetectors (QWIP) are all suitable detector material systems for tactical applications, in which some material systems are more mature than others. For strategic applications, such as exo-atmospheric interceptors and space-based surveillance sensors, the target is usually far away with a cooler temperature, under a cold background. The detection wavelength of the detector under this situation needs to be at very-long-wavelength region (> 12 micrometers) for efficient detection of the cool target. The current state of the art HgCdTe (MCT) based IR detectors have not met all these requirements, and QWIPs provide a useful alternative for VLWIR applications. In this presentation, an overview of VLWIR QWIPs is given and three detailed detector structures and performance are discussed.