INAS Detectors for Infrared Astronomy

We propose InAs as a superior alternative to mercury cadmium telluride (MCT) for NASAs astronomy applications in the visible to extended shortwave infrared (eSWIR) spectral band: 0.7 - 2.5 microns. A key performance parameter, the dark current density, can be achieved by cooling the InAs 20K more than MCT with 2.3 micron cutoff. In return, the InAs will extend spectral coverage to 3.0 microns and offer higher yield, lower cost, and greater availability due to the leveraging of mature group III-V growth/process equipment. In Phase I, we demonstrated an InAs focal plane array (FPA) with spectral response from 450 nm to 3000 nm, quantum efficiency ~ 70% in this wide band, and a low dark current that dropped exponentially with cooling. In Phase II, we will further improve material quality, expand array format to 1Kx1K, and deliver a megapixel camera to NASA for evaluation for astronomy. InAs as an alternative to MCT for infrared astronomy Same dark current as MCT with 20K of additional cooling Extension of cutoff wavelength from 2.3 microns (for MCT) to 3.0 microns Higher yield and lower cost than MCT = greater availability Much better image stability TECHNICAL OBJECTIVES Build on and improve Ph1 InAs material and processing Develop megapixel InAs FPA (1Kx1K on 18 micron pixel pitch) Develop anti-reflection coating covering 500-3000 nm spectral band Develop camera packaging of FPA PROPOSED DELIVERABLE InAs FPA Camera
Benefits: Space- and ground-based infrared astronomy James Webb Space Telescope (JWST) EUCLID Wide Field InfraRed Survey Telescope (WFIRST) Hyperspectral imaging Product inspection in pharmaceutical and agricultural produce industries Crop inspection and development Target recognition and identification for DOD