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30 August 2004 LWIR and VLWIR Hg1-xCdxTe photoconductors with improved responsivity
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Photoconductors based on multi-layer structure consists of homogeneous narrow-gap n-Hg1-xCdxTe absorbing layer (n-absorber) blocked by thin adjacent graded-gap Hg1-xCdxTe layers have been fabricated and examined. A possible giant increase in responsivity of Long-Wave Infrared (LWIR) photoconductor (spectral range from 8 to 14 μm) and Very Long-Wave Infrared (VLWIR) photoconductor (spectral range longer than 14 μm) at 78-100K operating temperature was predicted. Prediction is based on suggestion that interfaces in three-layer sensitive structure grown by MBE in single run and consists of n-absorber and adjacent graded-gap layers of native material and same type of conductivity will be free of both recombination centers and charge states. Theoretical analysis has shown that formation of diffusion barrier within graded-gap layers is occurred during illumination of photoconductor. That diffusion barrier prevents excess holes excited in homogenous absorber layer from moving to surfaces. Therefore excess holes will recombine preferably in active region of photoconductor, thus giving high quantum efficiency and good responsivity. Measurements performed on fabricated photoconductors showed near ideal background limited performance (BLIP) with significantly increased value of peak responsivity. Wide shape of spectral responsivity curves is evidence that surface recombination at interfaces was eliminated.
© (2004) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Galina V. Chekanova, Ivan Yu. Lartsev, Mikhail S. Nikitin, Viacheslav G. Artyushenko, Vladimir A. Lobachev, Albina A. Drugova, Viacheslav A. Kholodnov, and Jim T. Ingram "LWIR and VLWIR Hg1-xCdxTe photoconductors with improved responsivity", Proc. SPIE 5406, Infrared Technology and Applications XXX, (30 August 2004);

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