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Title: Progress Towards Competitive III-V Infrared Detectors: Fundamental Material Characterization and Techniques.


Abstract not provided.

Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
Report Number(s):
DOE Contract Number:
Resource Type:
Country of Publication:
United States

Citation Formats

Kadlec, Emil Andrew. Progress Towards Competitive III-V Infrared Detectors: Fundamental Material Characterization and Techniques.. United States: N. p., 2017. Web.
Kadlec, Emil Andrew. Progress Towards Competitive III-V Infrared Detectors: Fundamental Material Characterization and Techniques.. United States.
Kadlec, Emil Andrew. 2017. "Progress Towards Competitive III-V Infrared Detectors: Fundamental Material Characterization and Techniques.". United States. doi:.
title = {Progress Towards Competitive III-V Infrared Detectors: Fundamental Material Characterization and Techniques.},
author = {Kadlec, Emil Andrew},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 7

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  • Germanium Blocked Impurity Band (BIB) detectors require a high purity blocking layer (< 10 13 cm -3) approximately 1 mm thick grown on a heavily doped active layer (~ 10 16cm -3) approximately 20 mm thick. Epilayers were grown using liquid phase epitaxy (LPE) of germanium out of lead solution. The effects of the crystallographic orientation of the germanium substrate on LPE growth modes were explored. Growth was studied on substrates oriented by Laue x-ray diffraction between 0.02° and 10° from the {111} toward the {100}. Terrace growth was observed, with increasing terrace height for larger misorientation angles. It wasmore » found that the purity of the blocking layer was limited by the presence of phosphorus in the lead solvent. Unintentionally doped Ge layers contained ~10 15 cm -3 phosphorus as determined by Hall effect measurements and Photothermal Ionization Spectroscopy (PTIS). Lead purification by vacuum distillation and dilution reduced the phosphorus concentration in the layers to ~ 10 14 cm -3 but further reduction was not observed with successive distillation runs. The graphite distillation and growth components as an additional phosphorus source cannot be ruled out. Antimony (~10 16 cm -3) was used as a dopant for the active BIB layer. A reduction in the donor binding energy due to impurity banding was observed by variable temperature Hall effect measurements. A BIB detector fabricated from an Sb-doped Ge layer grown on a pure substrate showed a low energy photoconductive onset (~6 meV). Spreading resistance measurements on doped layers revealed a nonuniform dopant distribution with Sb pile-up at the layer surface, which must be removed by chemomechanical polishing. Sb diffusion into the pure substrate was observed by Secondary Ion Mass Spectroscopy (SIMS) for epilayers grown at 650 C. The Sb concentration at the interface dropped by an order of magnitude over ~ 1.5 μm. Layers grown at 550 C did not show significant Sb diffusion. Sn doped In 2O 3 (ITO) was studied for use in far infrared transparent low temperature contacts for BIB arrays. It was found that ~100 nm of ITO deposited on Ge remains electrically conducting at 4 K and is ~90% transparent in the far infrared. ITO should be suitable for passivating contacts to Ge BIB arrays.« less
  • The development of application programs for infrared spectroscopy has been an ongoing proposition for a number of years. This development, however, was accelerated with the advent of Fourier transform infared (FT-IR) instruments and their built-in mini-computers. The uses and pitfalls of several of these routines are discussed in this thesis. A least-squares curve resolving program has been developed and the use of this program is also discussed. The analysis of complex, multicomponent polymeric materials, such as coal and oil shale, by conventional infrared spectroscopy has been a difficult problem. The use of FT-IR spectroscopy for the qualitative and quantitative analysismore » of these types of materials is discussed. A characterization of oil shale from the Mahogany Zone of the Green River Formation has been obtained by FT-IR. A quantitative analysis of the mineral component by FT-IR spectroscopy is shown to be comparable to that obtained by x-ray diffraction when considering broad mineral types, i.e., carbonates. Methods for the FT-IR analysis of the organic component, both from the whole shale and from kerogen specimens, have been refined. There is a good correlation between the intensity of alkyl bands and Fisher assay yields. An assessment is made of the applicability of extinction coefficients obtained from paraffins to their use in quantitative analysis in oil shales. A quantitative analysis of OH content in coal by FT-IR is comparable to that done by other methods (i.e., chemical and NMR). An analysis is also made of the various types of OH groups in coal.« less
  • This research has shown that epilayers with residual impurity concentrations of 5 x 10 13 cm -3 can be grown by producing the purest Pb available in the world. These epilayers have extremely low minority acceptor concentrations, which is ideal for fabrication of IR absorbing layers. The Pb LPE growth of Ge also has the advantageous property of gettering Cu from the epilayer and the substrate. Epilayers have been grown with intentional Sb doping for IR absorption on lightly doped substrates. This research has proven that properly working Ge BIB detectors can be fabricated from the liquid phase as longmore » as pure enough solvents are available. The detectors have responded at proper wavelengths when reversed biased even though the response did not quite reach minimum wavenumbers. Optimization of the Sb doping concentration should further decrease the photoionization energy of these detectors. Ge BIB detectors have been fabricated that respond to 60 cm -1 with low responsivity. Through reduction of the minority residual impurities, detector performance has reached responsivities of 1 A/W. These detectors have exhibited quantum efficiency and NEP values that rival conventional photoconductors and are expected to provide a much more sensitive tool for new scientific discoveries in a number of fields, including solid state studies, astronomy, and cosmology.« less
  • High-purity and doped GaAs films have been grown by Liquid-phase epitaxy (LPE) for development of a blocked impurity band (BIB) detector for far-infrared radiation. The film growth process developed has resulted in the capability to grow GaAs with a net active impurity concentration below 1 x 10 13 cm -3, ideal for the blocking layer of the BIB detector. The growth of n-type LPE GaAs films with donor concentrations below the metal-insulator transition, as required for the absorbing layer of a BIB detector, has been achieved. The control of the donor concentration, however, was found to be insufficient for detectormore » production. The growth by LPE of a high-purity film onto a commercially grown vapor-phase epitaxial (VPE) n-type GaAs doped absorbing layer resulted in a BIB device that showed a significant reduction in the low-temperature dark current compared to the absorbing layer only. Extended optical response was not detected, most likely due to the high compensation of the commercially grown GaAs absorbing layer, which restricts the depletion width of the device.« less