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We present a detailed study of double barrier strained Al0.35Ga0.65As/AlAs/GaAs/In0.2Ga0.8As quantum well infrared photodetectors on GaAs substrate. Measurements were made on four different well widths active layers and on several mesa pixels with different optical coupling structures. We obtained responses peaked in the spectral range 3.6–4.6 μm. Based on the experimental results, we show that in the background limited regime, the impact ionization is the restrictive transport process for midwave detectors. We also demonstrate a 4 μm structure with the high background limited detectivity of 2×1011 Jones at 77 K and 9×1010 Jones at 110 K (2π field of view, 300 K background).

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Since 2005, Thales is successfully manufacturing QWIPs in high rate production through III-V Lab. All the early claimed advantages of QWIPs are now demonstrated. The versatility of the band-gap engineering allows the custom design of detectors to fulfill specific application requirements in MWIR, LWIR or VLWIR ranges. The maturity of the III-V microelectronics based on GaAs substrates gives uniformity, stability and high production rate. In this presentation we will discuss the specific advantages of this type of detector. An overview of the available performances and production status will be presented including under-development products such as dual band and polarimetric sensors.

A review of the III-V Lab activities in the field of quantum well infrared photodetectors (QWIPs) is presented. We discuss the specific advantages of this type of detector and present the production facilities and status. A large section is dedicated to broadband QWIPs for space applications and to QWIPs on InP for mid-wavelength infrared detection. We review the progress of QWIP technology for the next generation (dual band, polarimetric, and multispectral) of thermal imagers. Finally, the state-of-the-art of very long wavelength QWIPs is discussed. C 2011 Society of Photo-Optical Instrumentation Engineers (SPIE). IntroductionAt the III-V Lab, research on quantum well infrared photodetectors (QWIPs) has always been driven by the needs and constraints set by the operational systems. Reliable infrared (IR) cameras for Thales applications need high temperature operation (T FPA > 73 K), low integration time (T INT < 5 ms) to achieve high imaging rates and true microscanning, high instantaneous dynamic range ( + 50 • C) to accurately image objects much hotter than the background. They also need small pitch focal plane arrays (FPAs) (<25 μm) in order to get compact and low cost systems.In this context, parameters such as specific detectivity (D*) or ultimate background limited performance are no more relevant. Moreover, FPA uniformity, stability, peak wavelength reproducibility, and process mastering play an important role. These are reasons why at the III-V Lab, research relies on production facilities.QWIPs have been widely investigated for detection in the mid-wavelength (MW, 3 to 5 μm), long wavelength (LW,8 to