Development of quantum well infrared photodetectors in France

Abstract

Standard GaAs/AlGaAs quantum well infrared photodetectors (QWIPs) are now well established for LWIR detection. The main advantage of this technology is the duality with the technology of commercial GaAs devices. The second advantage widely claimed for QWIPs is the so-called band-gap engineering, allowing the custom design of the quantum structure to fulfill the requirements of specific applications such as multispectral detection. QWIPs are close to being optimized. The understanding of detection mechanisms has led to high performance QWIPs working at high temperature (above 77 K). However, as with all quantum detectors, the operating temperature of QWIPs is limited by the thermal current. A new skimmed architecture accommodating this offset has already been demonstrated. The optimization of a skimmed structure requires the modeling procedures and the process, to be adapted. We present the current status of QWIPs in France, including the latest performances achieved with both standard and skimmed architectures. We illustrate the development of our QWIPs by recent results on FPAs.