QWIP and MCT for Long Wavelength and Multicolor Focal Plane Array Applications,
ARMY RESEARCH LAB ADELPHI MD
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Infrared IR sensor technology is critical to all phases of ballistic missile defenses. Traditionally, material systems such as indium antimonide InSb, platinum silicide PtSi, mercury cadmium telluride MCT, and arsenic doped silicon Si As have dominated IR detection. Improvement in surveillance sensors and interceptor seekers requires large size, highly uniform and multicolor or multispectral IR focal plane arrays involving mid-wave, long-wave and very-long-wave IR regions. Among the competing technologies are the quantum well infrared photodetectors QWIP based on lattice matched GaAsAl GaAs and strained layer InGaAsAlGaAs material systems. In this paper, a discussion of cooled IR technology with emphasis on QWIP and MCT will be given. Details will be given concerning device physics, material growth, device fabrication, device performance, and cost effectiveness for long wavelength infrared, very long wavelength infrared, and multicolor applications. The conclusion drawn here is that even though QWIP cannot compete with MCT at the single device level, it has potential advantages over MCT for long wavelength and very long wavelength focal plane array applications in term of the array size, uniformity, operability, yield, reliability, and cost of the systems. QWIPs are especially promising for very-long-wave IR at low temperature operation, and when simultaneous multicolor detection using a single focal plane array is desired. Operating a very-long-wave IR focal plane array at low background is a big challenge to both MCT and QWIP, while QWIP has more potential to be realized due to its good device property at low temperature.
- Antimissile Defense Systems
- Infrared Detection and Detectors
- Quantum Theory and Relativity