Long-wavelength Ge/sub x/Si/sub 1-x//Si heterojunction infrared detectors and 400*400-element imager arrays

Heterojunction Ge/sub x/Si/sub 1-x//Si internal photoemission infrared detectors exhibiting nearly ideal thermionic-emission dark-current characteristics have been fabricated with cutoff wavelengths out to 16 mu m. High-quality imaging without uniformity correction has been demonstrated in the long-wavelength infrared (LWIR) spectral band for 400*400-element focal plane arrays consisting of Ge/sub 0.44/Si/sub 0.56/ detectors with a cutoff wavelength of 9.3 mu m and monolithic charged-coupled-device readout circuitry. The Ge/sub 0.44/Si/sub 0.56/ composition was chosen in order to obtain a barrier height low enough to yield a cutoff length within the LWIR band, but high enough to permit low dark-current operation at about 50 K.<
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