LWIR and VLWIR Hg<sub>1-x</sub>Cd<sub>x</sub>Te photoconductors with improved responsivity

Galina V. Chekanova; Ivan Yu. Lartsev; Mikhail S. Nikitin; Viacheslav G. Artyushenko; Vladimir A. Lobachev; Albina A. Drugova; Viacheslav A. Kholodnov; Jim T. Ingram

doi:10.1117/12.542056

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30 August 2004 LWIR and VLWIR Hg_1-xCd_xTe photoconductors with improved responsivity

Galina V. Chekanova, Ivan Yu. Lartsev, Mikhail S. Nikitin, Viacheslav G. Artyushenko, Vladimir A. Lobachev, Albina A. Drugova, Viacheslav A. Kholodnov, Jim T. Ingram

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Proceedings Volume 5406, Infrared Technology and Applications XXX; (2004) https://doi.org/10.1117/12.542056
Event: Defense and Security, 2004, Orlando, Florida, United States

Abstract

Photoconductors based on multi-layer structure consists of homogeneous narrow-gap n-Hg_1-xCd_xTe absorbing layer (n-absorber) blocked by thin adjacent graded-gap Hg_1-xCd_xTe 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.

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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 Hg_1-xCd_xTe photoconductors with improved responsivity", Proc. SPIE 5406, Infrared Technology and Applications XXX, (30 August 2004); https://doi.org/10.1117/12.542056

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