These detectors may be the next generation of band-gap engineered, large format infrared detector arrays with substantially higher quantum efficiencies than existing quantum well-based (QWIPs) detectors and provide a competitive alternative to the current state-of-the-art mercury cadmium telluride detector arrays. Strained Layer Superlattice (SLS) detectors are a new class of detectors. However, in selecting a detector many more variables need to be considered such as: the costs associated with a particular IR technology, the array format availability, operating conditions, reliability, level of manufacturing complexity, technical support, reliability, replaceability and compatibility with interfacing technologies (readout ICs, frame rates etc.). This sensitivity is generally determined by the quantum efficiency and the noise characteristics of the detector under its operating conditions. Implicit in this expectation is the necessary sensitivity of the specific detector technology selected for a given mission. The performance of the detector arrays generally defines the ultimate performance of the instrument. However, near term prospects include upcoming Landsat missions, possibly exoplanet exploration, planetary observations yet to be defined. This technology requires further validation before it can be considered for existing missions. We believe that actual IR imaging of external environment scenery will prove most valuable. Before we embark on an ambitious in-house program to design and fabricate SLS detectors it would be very valuable to build an IR camera system using the existing SLS array we currently have and perform some local field tests. However, along with the dramatic improvement in QE we measured much higher dark current and the array was quite non-uniform. The most important result of that investigation was the verification of the (unexpected) very high QE. In our FY12 IRAD we obtained a test SLS array and performed extensive tests to ascertain the veracity of researcher claims, as well as to assess the potential applications to NASA missions from a practical infusion standpoint. Warmer and more stable focal planes lead to simpler instrument designs which result in higher reliability, longer mission lifetimes and reduced costs. The anticipated advantages of SLS detector technology over existing IR detectors are: high sensitivity, band-gap tunable wavelength response (similar to QWIPs), warmer operating temperatures, array spectral uniformity (yet to be realized), high temporal stability, relatively low cost of manufacturing, scalability (to very large format arrays) and multiple vendor sources all contributing to higher performing scientific instruments. In our FY12 IRAD “Strained Layer Superlattice Infrared Detector Array Characterization” we verified that these devices exhibit a dramatic increase in quantum efficiency (QE) over quantum well infrared photodetectors (QWIPs) and are approaching QE values comparable with mercury cadmium telluride and indium antimonide detectors. This a major technological breakthrough, yet before we embark on an expensive in-house program to design and fabricate SLS detectors it would be very valuable to build an IR camera system using the existing SLS array we currently have and perform experimental field tests. Previously, (in our FY12 IRAD “Strained Layer Superlattice Infrared Detector Array Characterization”) we verified that these devices exhibit a dramatic increase in quantum efficiency (QE) over quantum well infrared photodetectors (QWIPs) and are approaching QE values comparable with mercury cadmium telluride and indium antimonide detectors. Strained Layer Superlattice (SLS) detectors are a new class of detectors which may be the next generation of band-gap engineered, large format infrared detector arrays with substantially higher quantum efficiencies than existing quantum well infrared photodetectors (QWIPs) and provide a competitive alternative to the current state-of-the-art mercury cadmium telluride and QWIP detector arrays.
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