Tsybrii Z. Physical and technological grounds of IR and THz HgCdTe-detectors and IR blocking elements development

The dissertation is devoted to the determination of the main technological processes that limit the threshold parameters of photodetectors based on narrow-gap HgCdTe semiconductors and the study of their physical nature, which allowed for the first time in Ukraine to develop the basics of technology for discrete and multi-element two-color IR and THz detectors of third generation. A thorough analysis of physical and chemical processes that occur during the formation of IR detectors based on HgCdTe was carried out. This allowed to study, optimize and substantiate the modes of key technological stages of their formation and to develop unique technological methods of manufacturing IR and THz MCT detectors. The topologies of IR multielement photodiode arrays with different format and size of sensitive elements based on MCT epitaxial layers, as well as discrete photodiodes, were developed. The technological process of IR detectors manufacturing based on epitaxial layers of HgCdTe has been worked out. The limit values of temperature and mechanical loads on the epitaxial layers of HgCdTe, which should be taken into account in the technology of manufacturing detectors based on HgCdTe were esteblished; low-temperature modes of formation of protective CdTe coatings were developed, the physical properties of which meet the requirements for passivation coatings; physical and chemical processes at the metal / HgCdTe interface were studied, which occur at the developed low-temperature modes of formation of two-layer ohmic contacts to HgCdTe epitaxial layers, with both electronic and hole type conductivity. An ohmic behavior of contacts does not depend on the type of metal and that indicates about enrichment by carriers of the near-surface layer, due to the pinning of the Fermi level. Mid-wave and long-wave IR photodiodes of MCT with different topology were fabricated and their electrical and photoelectrical characteristics were investigated. The obtained experimental values of HgCdTe mid-wave and long-wave IR photodiodes detectivity indicate their functionality in modes close to those limited by background radiation. Manufactured THz hot electron bolometers based on MCT were used to form an 8-element linear array for application in the sub-THz (???? ≈ 140 GHz) imaging system. The obtained THz images of the packaged items demonstrated satisfactory spectral resolution of the sub-THz imaging system. The possibility of realization of two- or multiband detectors based on epitaxial layers of HgCdTe in the IR and THz spectral range was shown. Dual-band detectors based on MCT hot electron bolometers integrated with metal antennas, which have demonstrated a response to THz radiation (based on electron gas heating in a bipolar semiconductor) are also sensitive in the IR range (due to interband absorption) with a cutoff wavelength, which corresponds to chemical composition of HgCdTe. For the first time, the mechanisms of operation of the selective filters based on composite structures AlN (MgO) / polymeric film, which block infrared radiation and are transparent in the visible and THz bands of the spectrum, have been reasoned. It is proved that the improved operational capabilities are due to the extension of the band of residual rays for AlN in the range of 10.5 - 17 μm, which is due to their polycrystalline nanostructured structure. Their functionality has been experimentally proven