• Journal of Electrochemical Science and Technology
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• 제3권1호
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• pp.35-43
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• 2012

Highly ordered and perforated anodic aluminum oxide membranes were prepared by anodic oxidation and subsequent removal of the barrier layer. By using these homemade anodic aluminum oxide membranes as templates, metal selenide nanowires and nanotubes were synthesized. The structure and composition of these one-dimensional nanomaterials were studied by field emission scanning electron microscopy as well as transmission electron microscopy and energy dispersive X-ray spectroscopy. The growth process of metal selenide inside anodic aluminum oxide channel was traced by investigating the series of samples using scanning electron microscopy after reacting for different times. Straight and dense copper selenide and silver selenide nanowires with a uniform diameter were successfully prepared. In case of nickel selenide, nanotubes were preferentially formed. Phase and crystallinity of the nanostructured materials were also investigated.

• ETRI Journal
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• 제27권4호
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• pp.411-417
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• 2005

$Pr^{3+}-doped$ selenide glass optical fiber, which guarantees single-mode propagation of above at least 1310 nm, has been successfully fabricated using a Ge-Ga-Sb-Se glass system. Thermal properties such as glass transition temperature and viscosity of the glasses have been analyzed to find optimum conditions for fiber drawing. Attenuation loss incorporating the effects of an electronic band gap transition, Rayleigh scattering, and multiphonon absorption has also been theoretically estimated for the Ge-Ga-Sb-Se fiber. A conventional double crucible technique has been applied to fabricate the selenide fiber. The background loss of the fiber was estimated to be approximately 0.64 dB/m at 1650 nm, which can be considered fairly good. When excited at approximately 1470 nm, $Pr^{3+}-doped$ selenide fiber resulted in amplified spontaneous emission and saturation behavior with increasing pump power in a U-band wavelength range of 1625 to 1675 nm.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2012년도 춘계학술발표대회
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• pp.98.2-98.2
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• 2012

Thin film solar cells are growing up in the market due to their high efficiency and low cost. Especially CdTe and $CuInGaSe_2$ based solar cells are leading the other cells, but due to the limited percentage of the elements present in our earth's crust like Tellurium, Indium and Gallium, the price of the solar cells will increase rapidly. Copper Zinc Tin Sulfide (CZTS) and Copper Zinc Tin Selenide (CZTSe) semiconductor (having a kesterite crystal structure) are getting attention for its solar cell application as the absorber layer. CZTS and CZTSe have almost the same crystal structure with more environmentally friendly elements. Various authors have reported growth and characterization of CZTSe films and solar cells with efficiencies about 3.2% to 8.9%. In this study, a novel method to prepare CZTSe has been proposed based on selenization of stacked Copper Selenide ($Cu_2Se$), Tin Selenide ($SnSe_2$) and Zinc Selenide (Zinc Selenide) in six possible stacking combinations. Depositions were carried out through RF magnetron sputtering. Selenization of all the samples was performed in Close Space Sublimation (CSS) in vacuum at different temperatures for three minutes. Characterization of each sample has been performed in Field Emission SEM, XRD, Raman spectroscopy, EDS and Auger. In this study, the properties and results of $Cu_2ZnSnSe_4$ thin films grown by selenization will be presented.

• 한국전기전자재료학회논문지
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• 제30권11호
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• pp.745-750
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• 2017

Terahertz time-domain spectroscopy has been used to study the optical properties of $Pr^{3+}-doped$ selenide glasses. The complex refractive indexes of $Pr^{3+}-selenide$ glasses were measured in a frequency range from 0.3 to 1.5 THz. The real and imaginary refractive indexes increased with increasing frequency and $Pr^{3+}$ ion concentration. The obtained result indicated that the phonon modes of the $Pr^{3+}-doped$ selenide glasses shift to lower frequencies with the concentration of $Pr^{3+}$ ions. The theory of far-infrared absorption in amorphous materials was used to analyze the results. The measured data showed that the disorder-induced terahertz absorption increased with increasing $Pr^{3+}$ ion concentration.

• 한국광물학회지
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• 제24권3호
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• pp.217-224
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• 2011

철환원 박테리아인 미시가넨시스를 이용하여 용존 셀레늄을 제거할 때, 물 속의 다른 금속성분들인 철, 황산염, 그리 구리가 미칠 수 있 영향을 살펴보았다. 미시가넨시스 박테리아는 산화수가 4가인 산화 셀레나이트(2 mM)를 셀레나이드로 환원시키고 물속의 셀레늄 농도를 점차 감소시켰다. 환원된 셀레나이드는 용존 2가 철과 결합하여 나노입자 크기의 철-셀레나이드로 침전되었다. 용존 황산염과 구리는 미생물의 셀레나이트 환원작용에 부정적인 영향을 끼쳤는데, 특히 구리 성분은 미생물에 대해 독성으로 작용하여 셀레나이트 제거가 원활히 이뤄지지 못하게 하였다. 이러한 결과로부터 알 수 있는 것은 셀레늄으로 오염된 현장을 미생물로 정화할 때 황산염 혹은 구리의 농도 분포와 양을 충분히 고려해야 한다는 사실이다. 궁극적으로 미생물에 의한 철-셀레나이드 광물형성작용은 지하수를 따라 원거리로 이동할 수 있는 셀레늄의 확산을 억제하는 중요한 수단이라고 볼 수 있다.

• 대한화학회지
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• 제20권4호
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• pp.280-289
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• 1976

$Ag_2Se$ 전극을 제조하고 은이온에 대한 지시전극으로서의 성질을 조사하였다. Epoxy 수지를 Ag_2Se 전극의 binder로서, Silver paste를 감응막과 은판의 접착제로서 사용하였다. 감응막은 10ton/$cm^2$로 가압성형 한다음 질소분위기에서 200${\sim}$$500^{\circ}C$로 sintering한 후 전극을 제조한 결과sintering 하지않은 전극보다 감응성이 우수하고 견고하였다. 또한 $Ag_2Se$전극보다 감응성이 우수하였다. 은이온농도의 변화에 따르는 감응도는 10-6M까지 직선관계를 유지하였다. 대부분의 중금속 이온은 방해하지 않으나 수은(II) 이온이 크게 방해를 하였으며 음이온인 halide, cyanide, thiocyanate 이온의 방해는 더욱 심하였다. 반면 이전극은 halide 이온 정량시 전위차적정법으로 사용할 수 있음을 알았다.

• 전기학회논문지
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• 제59권3호
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• pp.594-598
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• 2010

We studied on the field emission properties of double-walled carbon nanotubes (DWCNTs) coated with lead selenide (PbSe) nanoparticles. PbSe nanoparticles were uniformly attached on the surface of the DWCNTs by a simple chemical process. The PbSe-coated DWCNTs showed highly increased emission current density and enhanced emission stability over 20 h, compared with raw DWCNTs. We consider that the enhanced field emission properties of PbSe-coated DWCNTs were attributed to the increased field enhancement factor and lowered work function of the emitters.

• Applied Microscopy
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• 제26권4호
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• pp.411-420
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• 1996

A zinc-specific method (selenium method) has been employed to identify the zinc-containing cells in the cerebellum of the rats. When rats were allowed to survive 24 hours after the sodium selenite administration, zinc selenide reaction products formed in zinc-containing cellular boutons are retrogradely transported to the somata of those boutons. And the zinc selenide products accumulated in somata of the cells can be rendered visible by silver amplification of developer. Zinc-containing cells identified by the method were Bergmann glial and granule cells. Labeled zinc-containing cells were absent in molecular layer and white matter of the cerebellum. In ultrastructural level, the zinc selenide products were located in lysosomes of somata of the zinc-containing cells.

• 한국전기전자재료학회논문지
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• 제22권5호
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• pp.382-385
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• 2009

In this study, we studied switching characteristics of germanium selenide(Ge-Se)/silver(Ag) contact formed by photodoping for use in programmable metallization cell devices. We have been investigated the switching characteristics of Ag-doped chalcogenide thin films. Changed resistance range by direction of applied voltage is about $1\;M{\Omega}$ $\sim$ hundreds of $\Omega$. The cause of these resistance change can be thought the same phenomenon such as resistance variation of PMC-RAM. The results imply that the separated Ag-ions react the atoms or defects in chalcogenide thin films.

• 대한화학회지
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• 제66권5호
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• pp.341-348
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• 2022

In this work, radio frequency magnetron sputtering was used to deposit zinc selenide thin films on p-type silicon (100) wafers and glass substrates in a high vacuum chamber. Several surface characterization instruments were implemented to study the thin films. X-ray photoelectron spectroscopy results revealed that oxidized Zn bound to Se (Zn-Se) at 1022.7 ± 0.1 eV becomes the dominant oxidized species when Se concentration exceeds 70%. Scanning electron microscopy coupled with energy dispersive spectroscopy showed that incorporating Se in Zn thin films will lead to formation of ZnSe grains on the surface. Contact angle measurements indicated that ZnSe-60 exhibited the lowest total surface free energy value of 24.94 mN/m. Lastly, ultraviolet-visible spectrophotometry and ultraviolet photoelectron spectroscopy data evinced that the energy band gap gradually increases with increasing Se concentration with ZnSe-70 having the highest work function value of 4.91 eV.