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A modular focal-plane array composed of a SWIR photovoltaic HgCdTe/Si hybrid module has been developed for NASA Earth Resources application. Detector arrays have been fabricated for use in the 1.0-2.5-µm wavelength regime using ion-implanted planar photodiodes formed in liquid-phase epitaxial layers grown on CdZnTe substrates. The resulting diodes have shown R_{0}A_{J} products as high as 2 × 105Ω . cm2at 200 K. The detector design features a gate and a guard structure to reduce leakage current and provide improved optical definition. The multiplexer is a low-noise n-channel direct readout circuit with a 256 : 2 architecture. When the hybrid is operated at 145 K, nonuniformity of responsivity under uniform illumination is less than 8 percent, operability is 99 percent, D* is 82-percent BLIP at 4.7 × 1013ph/cm2. s for a 50-percent quantum efficiency detector, the nonlinearity of the modules is less than 1 percent, and the crosstalk is less than 5 percent. |
