• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.3977-3980
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• 2012

Nanostructured thermoelectric bismuth telluride ($Bi_2Te_3$) powders with various morphologies, such as nanoplates, nanorods, and nanotubes, were prepared by a hydrothermal method based on the reaction between $BiCl_3$, Te, and sodium ethylenediaminetetraacetate ($Na_2$-EDTA) at 150, 180, and $210^{\circ}C$. The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), and selected area electron diffraction (SAED). The effect of reaction temperature on the morphology of the $Bi_2Te_3$ particles was investigated, and the possible mechanism of morphology control was proposed.

• Proceedings of the KIEE Conference
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• 2003.07c
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• pp.1407-1409
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• 2003

The results of investigations of $Ag_2Te$ crystal is presented. $Ag_2Te$ crystal was grown by the Bridgman method. The $Ag_2Te$ crystal was an monoclinic structure with lattice constance a = 8.1686, b=9.0425, c=8.0065. Hall effect shows a n-type conductivity in the $Ag_2Te$ crystal. The electrical resistivity values was $1.080e^{-3}cm$ and electron mobility was $-5.4810^{3}cm^{2}$/Vsec at room temperature(RT).

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.684-685
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• 2006

In the present study, the powder metallurgical fabrication of $Bi_{0.4}Te_3Sb_{1.6}$ thermoelectric materials has been studied with specific interest to control the microstructure by the mechanical grinding process. The $Bi_{0.4}Te_3Sb_{1.6}$ thermoelectric powders with a various particle size distribution were prepared by the combination of the mechanical milling and blending processes. The specific electric resistivity of the $Bi_{0.4}Te_3Sb_{1.6}$ sintered bodies mainly depended on the orientation of the crystal structure rather than the particle size of the raw powders.

• Proceedings of the KSEEG Conference
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• 2003.04a
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• pp.178-179
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• 2003

Mesothermal, tellurium-bearing gold-silver vein mineralization of the Yuryang mine was formed in mineralogically complex quartz-sulfide veins that filled the fault fractures in Precambrian gneiss within Gyeonggi Massif. Ore grades average 179 g/ton gold with a gold/silver ratio of 1.5 : 1. Ore mineralization was deposited in single stage. Major ore mineralization can be divided into two mineralization phases with increasing paragenetic time: Fe-sulfide and base-metal mineralization phase $\rightarrow$ telluride mineralization phase. (omitted)

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1996.06a
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• pp.516-518
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• 1996

Bimuth telluride type thermoelectrics are prepared by AC current applied got pressing method. It is possible to minimize the defects arising from the vaporization of Te, because of the very short processing time. The optimum conditions for the got pressing of 95mol% $Bi_2Te_3$-5mol%$Bi_2Se_3$ themoelectrics are sintered at $400^{\circ}C$, for 2min. with 1500 kgf/$cm^2$ from the particle size of 125 to 250 $\mu$m rang of powder. the resulted Z value (figure of merit) was 2.2$\times$10-3deg-1.

• Nuclear Engineering and Technology
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• v.54 no.12
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• pp.4620-4624
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• 2022

Several cadmium zinc telluride (CZT) crystals were fabricated into radiation detectors using methods that included slicing, dicing, lapping, polishing, and chemical etching. A wet passivation with sodium hypochlorite (NaOCl) was then carried out on the Br-etched detectors. The Te-rich layer on the CZT surface was successfully compensated to the Te oxide layer, which was analyzed with X-ray photoelectron spectroscopy data of both a Br-etched crystal and a passivated CZT crystals. We confirmed that passivation with NaOCl improved the transport property by analyzing the mobility-lifetime product and surface recombination velocity. The electrical and spectroscopic properties of large volume detectors were compared before and after passivation, and then the detectors were observed for a month. Both bar and quasi-hemispherical detectors show an enhancement in performance after passivation. Thus, we could identify the effect of NaOCl passivation on large volume CZT detectors.

• Journal of Radiation Industry
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• v.17 no.1
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• pp.119-125
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• 2023

Burnup of spent nuclear fuel should be determined accurately for the safety storage of spent nuclear fuel. In this study, a gamma detection system was developed as a part of basic research to measure the burnup of spent nuclear fuel, and its performance was evaluated using a calibration source. The prototype of the gamma detection system was based on a semiconductor sensor using a CZT (Cadmium Zinc Telluride). For quantitative evaluation, tests were conducted using ¹³⁷Cs, ¹³⁴Cs and ²⁵²Cf calibration source. In the performance evaluation, Its field applicability was verified by assessing the energy resolution, the detection linearity and the shielding attenuation according to the nuclide.

• The Korean Journal of Nuclear Medicine Technology
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• v.20 no.2
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• pp.49-53
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• 2016

Purpose Recently, Cadmium-zinc-telluride (CZT) semiconductor myocardial SPECT (Single Photon Emission Computed Tomography) has been used myocardial scintigraphy. In this study, the performance of Semiconductor SPECT and conventional SPECT systems was compared by a comprehensive analysis of phantom SPECT images. Materials and Methods Methods: We evaluated the DSPECT CZT SEPCT (Spectrum-dynamic) and INFINA conventional (GE). Physical performance was compared on reconstructed SPECT images from a phantom. Results For count sensitivity on cardiac phantom images ($counts{\cdot}sec^{-1}{\cdot}MBq^{-1}$), DSPECT had a sensitivity of conventional SPECT. This classification was similar to that of myocardial counts normalized to injected activities from phantom images (respective mean values, $counts{\cdot}sec^{-1}{\cdot}MBq^{-1}$: 195.83 and 52.83). For central spatial resolution: DSPECT, 9.47mm; conventional SPECT, 16.90mm. For contrast-to-noise ratio on the phantom: DSPECT, 4.2; conventional SPECT, 3.6. Conclusion The performance of CZT cameras is dramatically higher than that of conventional SPECT. However, CZT cameras differ in that spatial resolution and contrast-to-noise ratio are better with conventional SPECT, whereas count sensitivity is markedly higher with the DSPECT.

• Transactions on Electrical and Electronic Materials
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• v.15 no.5
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• pp.257-261
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• 2014

Multilayered CdTe/PSS films were prepared by the electrostatic self-assembly method in an aqueous medium. Positively-charged cadmium telluride (CdTe) nanoparticles and anionic polyelectrolyte, poly (sodium 4-styrene sulfonate) (PSS) were assembled alternately in order to build up a multilayered film structure. A linear proportion of absorbance to the number of bilayers suggests that an equal amount of CdTe was adsorbed after each dipping cycle, which resulted in the buildup of a homogenous film. The binding energies of elements (Cd and Te) in multilayered CdTe/PSS film shifted from those of the CdTe nanoparticles in the pure state. This result indicates that the interfacial electron densities were redistributed by the strong electrostatic interaction between the oppositely-charged CdTe and PSS. Electrochemical properties of the multilayered CdTe/PSS films were studied in detail by cyclic voltammetry (CV).

• Journal of Institute of Convergence Technology
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• v.3 no.1
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• pp.51-54
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• 2013

Cadmium telluride(CdTe) nanowires were successfully synthesized from individual nanoparticles via self-assembly and the evolutionary process was investigated. The oxidation of tellurium ions on CdTe nanoparticles resulted in the organization of individual nanoparticle into twisted-nanoribbons. The nanoparticles self-assembled to twisted ribbons under light while nanoparticles under dark transformed to straight nanowires made of several layers of individual nanoparticles. The images of nanoribbons were analysed based on transmission electron microscopy and scanning electron microscopy. The photoluminescence was blue-shifted from 555 to 545nm.