TECHNIQUES TO IMPROVE THE QUANTUM EFFICIENCY OF LWIR SLS FPAs

Antimony-based type-II strained layer superlattice focal plane arrays (SLS FPAs) now achieve maximum quantum efficiencies (QE) in the longwave infrared (LWIR) of 50% (cutoff ~ 10-11 microns) and 40% (cutoff ~ 12-13 microns) in commercial production. With a couple changes to the material design, we think we can increase these QE numbers to 70% and 60%, respectively. Our optimism is based on our prior design attempts to increase the QE, combined with observation of material growth effects on QE. In Phase I, we will demonstrate a FPA with improved QE using SLS material that combines these techniques. In Phase II, we will optimize material design, maximize QE, and deliver a camera with a SLS FPA with the highest possible QE. Increasing the QE of FPAs will increase imaging sensitivity and detection range and benefit applications as diverse as infrared astronomy, missile detection and tracking, and imaging very small gas leaks.
Benefits: 1) LANDSAT Thermal InfraRed Sensor (TIRS) 2) Compact Thermal Imager (CTI) 3) Detection, tracking and chemical analysis of fires and gas leaks 4) Mapping and analysis of forests and vegetation 5) Space-based astronomy, e.g. future versions of the Spitzer Space Telescope 6) Climate Absolute Radiance and Refractivity Observatory (CLARREO) 7) BOReal Ecosystem Atmosphere Study (BOREAS) 8) Other infrared earth observing missions 9) Atmospheric mapping 10) Pollution chemistry 1) Gas leak detection and identification for the petrochemical, gas, and mining industries 2) Crop health monitoring and analysis 3) Missile detection for countermeasures systems 4) Thermography 5) Product inspection for pharmaceutical and agricultural industries 6) Security and surveillance