Advanced Hg_(1-x)Cd_(x)Te detectors based on MBE-grown multi-layer structures for IR spectroscopy and synergy with IR-fiber optics

摘要

High performance large active area photoconductors based on MBE-grown multi-layer structures consist of homogeneous narrow-gap n-Hg_(1-x)Cd_(x)Te absorbing layer (n-absorber) blocked by thin adjacent graded-gap Hg_(1-x)Cd_(x)Te layers have been fabricated and examined. Large active area (from 0.25 mm×0.25 mm to 2.25 mm×2.25 mm) Hg_(1-x)Cd_(x)Te photoconductors with improved responsivity in Mid-Wave 3.0-5.5 μm (MWIR); Long-Wave 8-14 μm (LWIR) and Very Long-Wave 14-20 μm (VLWIR) infrared spectral ranges are very attractive for use in state-of-the art IR imaging, analytical and spectroscopic equipment. Synergy of advanced Hg_(1-x)Cd_(x)Te detectors with IR-fiber optics, especially based on polycrystalline infrared (PIR-) fiber (4-18 μm) cables and bundles, provides above mentioned equipment with qualitatively new possibility like as remote probing of the objects which are difficult to access or beyond direct optical access. Availability of innovative Hg_(1-x)Cd_(x)Te epitaxial material (half-finished products of photoconductors - three-layer sensitive structures grown by MBE in single run) open perspective to manufacture and offer improved detectors for much number of applications. Low temperature MBE growth technique provides better tuning of detectors' spectral responsivity curves to the ordered spectral ranges. Measurements performed on fabricated photoconductors showed significantly increased value of peak responsivity and high level of detectivity.