• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.23 no.8
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• pp.627-631
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• 2010

ZnS:Mn yellow phosphors doped with Cu for white light emitting diodes were synthesized by solid state reaction method. The optical properties and structures of ZnS:Mn,Cu phosphors were investigated by x-ray diffraction, photoluminescence, and scanning electro microscopy. Photoluminescence excitation spectra originated from $Mn^{2+}$ were ranged from 450 nm to 500 nm. The yellow emission at around 580 nm was associated with $^4T_1{\rightarrow}^6A_1$ transition of $Mn^{2+}$ ions in ZnS:Mn,Cu phosphors. The highest photoluminescence intensity of the phosphors under 405 nm excitation was obtained at Cu concentration of 0.02 mol%. The enhanced photoluminescent intensity in the ZnS:Mn,Cu phosphors was interpreted by energy transfer from Cu to Mn.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.121-124
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• 1998

Generally the structure of powder electroluminescent devices (PELDs) on ITO-film was makeup of the ZnS:Cu phosphor layer and BaTiO$_3$ insulating layer. The active layer, which consists of a suitably doped ZnS powder mixed in a dielectric, is sandwiched between two electrodes; one of which are ITO film and the other is aluminum. In this paper, three kinds of powder eleotroluminescent devices (PELDs) : WK-A(ITO/BaTiO$_3$/ZnS:Cu/Silver paste). WK-B(ITO/BaTiO$_3$+ZnS:Cu/Silver paste) and WK-C(ITO/BaTiO$_3$/ZnS:Cu/BaTiO$_3$/Silver paste), fabricated by spin coating method, were investigated. To evaluate the luminescence properties of three kinds of PELDs, EL emission spectroscopy, transferred charge density and time response of EL emission intensity under square wave voltage driving were measured.

• Bulletin of the Korean Chemical Society
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• v.35 no.1
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• pp.189-196
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• 2014

Water dispersible ZnS based nanocrystals: ZnS (blue), ZnS:Cu (green) and ZnS:Mn (yellow-orange) were synthesized by capping the surface of the nanocrystals with a mercaptopropionic acid (MPA) molecule. The MPA capped ZnS based nanocrystal powders were characterized by using XRD, HR-TEM, EDXS, FT-IR, and FT-Raman spectroscopy. The optical properties of the colloidal nanocrystals were also measured by UV/Vis and photoluminescence (PL) spectroscopies in aqueous solvents. The PL spectra showed broad emission peaks at 440 nm (ZnS), 510 nm (ZnS:Cu) and 600 nm (ZnS:Mn), with relative PL efficiencies in the range of 4.38% to 7.20% compared to a reference organic dye. The measured average particle sizes from the HR-TEM images were in the range of 4.5 to 5.0 nm. White light emission was obtained by mixing these three nanocrystals at a molar ratio of 20 (ZnS):1 (ZnS:Cu):2 (ZnS:Mn) in water. The measured color coordinate of the white light was (0.31, 0.34) in the CIE chromaticity diagram, and the color temperature was 5527 K.

• Korean Journal of Materials Research
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• v.23 no.6
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• pp.304-308
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• 2013

The effect of a sputter deposition sequence of Cu, Zn, and Sn metal layers on the properties of $Cu_2ZnSnS_4$ (CZTS) was systematically studied for solar cell applications. The set of Cu/Sn/Zn/Cu multi metal films was deposited on a Mo/$SiO_2$/Si wafer using dc sputtering. CZTS films were prepared through a sulfurization process of the Cu/Sn/Zn/Cu metal layers at $500^{\circ}C$ in a $H_2S$ gas environment. $H_2S$ (0.1%) gas of 200 standard cubic centimeters per minute was supplied in the cold-wall sulfurization reactor. The metal film prepared by one-cycle deposition of Cu(360 nm)/Sn(400 nm)/Zn(400 nm)/Cu(440 nm) had a relatively rough surface due to a well-developed columnar structure growth. A dense and smooth metal surface was achieved for two- or three-cycle deposition of Cu/Sn/Zn/Cu, in which each metal layer thickness was decreased to 200 nm. Moreover, the three-cycle deposition sample showed the best CZTS kesterite structures after 5 hr sulfurization treatment. The two- and three-cycle Cu/Sn/Zn/Cu samples showed high-efficient photoluminescence (PL) spectra after a 3 hr sulfurization treatment, wheres the one-cycle sample yielded poor PL efficiency. The PL spectra of the three-cycle sample showed a broad peak in the range of 700-1000 nm, peaked at 870 nm (1.425 eV). This result is in good agreement with the reported bandgap energy of CZTS.

• Journal of Animal Science and Technology
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• v.44 no.4
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• pp.399-406
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• 2002

An experiment was conducted to investigate the effects of supplemental copper or/and zinc methionine chelates(Cu-Met or/and Zn-Met) on the performance, nutrient digestibility, serum IgG level, gizzard erosion, and the contents of Cu and Zn in liver and excreta of broiler chickens. One thousand d-old broiler chickens (Ross$^{(R)}$) were assigned to 4 treatments: control, 100 ppm Cu in methionine chelate(Cu-Met), 100 ppm Zn in methionine chelate(Zn-Met) and 100 ppm Cu plus 100 ppm Zn in methionine chelate(Cu-Zn-Met). Each treatment had five replications of 50 (25 male + 25 female) birds each. Average weight gains of chicks fed chelated Cu or/and Zn were significantly higher than that of chicks fed the control (P<0.05). Moreover, feed conversion rates of chicks were better in the chicks fed chelated Cu or/and Zn than in the chicks fed the control (P<0.05). The birds fed the chelated Cu and Zn(Cu-Zn-Met) tended to perform the best growth rate and feed conversion rate. Nutrient digestibilities were not affected by the dietary treatments. Serum IgG level of chicks fed Cu-Zn-Met was significantly higher than that of chicks fed the control (P<0.05). Gizzard erosion index was not significantly different among the treatments. The contents of Cu and Zn in liver were not significantly affected by the dietary treatments. The excreta contents of Cu or/and Zn were significantly high in the birds fed supplementary Cu or/and Zn. It was concluded that dietary supplementation of Cu or/and Zn in methionine chelated form improved growth and feed conversion efficiency of broilers.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.3
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• pp.138-143
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• 2002

In this study, ZnS: Cu nano-crystals are synthesized by solution synthesis technique (SST). The structural properties such as crystal structure and particle morphology, and the optical properties such as light absorption/transmittance, energy bandgap, and photoluminescence (PL) excitation/emission are investigated. In an attempt to realize the Cu-doping easiness, the synthesis temperature (~$80^{\circ}C$) is applied to the synthesis bath, and the thiourea is used as sulfur precursor, unlike other general chemical synthesis route. Both undoped ZnS and ZnS : Cu nano-crystals have the cubic crystal structure and have the spherical particle shape. The position of light absorption edge is ~305 nm, indicating the occurrence of quantum size effect. The PL emission intensity and line-width are maximum and minimum, respectively, for Cu-doping concentration 0.03M. In particular, the dependence of PL intensity and line-width on the Cu-doping concentration for ZnS : Cu nano-crystals synthesized by SST is reported for the first time in this study. Experimental results of the absorption edge and the PL excitation show that the main emission peak of ZnS : Cu nano-crystals (~510 nm) in this study is due to the radiative recombination center in the energy bandgap induced by Cu dopant.

• Advances in nano research
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• v.5 no.3
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• pp.193-201
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• 2017

ZnO, ZnO: Cu, Ga, and ZnO: Cu, Ga, Ag thin films were obtained by oxidization of ZnS and ZnS: Cu, Ga films deposited onto glass substrates by electron-beam evaporation from ZnS and ZnS: Cu, Ga targets and from ZnS: Cu, Ga film additionally doped with Ag by the closed space sublimation technique at atmospheric pressure. The film thickness was about $1{\mu}m$. The oxidation was carried out at $600-650^{\circ}C$ in air or in an atmosphere containing water vapor. Structural characteristics were investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM). Photoluminescence (PL) spectra of the films were measured at 30-300 K using the excitation wavelengths of 337, 405 and 457.9 nm. As-deposited ZnS and ZnS: Cu, Ga films had cubic structure. The oxidation of the doped films in air or in water vapors led to complete ZnO phase transition. XRD and AFM studies showed that the grain sizes of oxidized films at wet annealing were larger than of the films after dry annealing. As-deposited doped and undoped ZnS thin films did not emit PL. Shape and intensity of the PL emission depended on doping and oxidation conditions. Emission intensity of the films annealed in water vapors was higher than of the films annealed in the air. PL of ZnO: Cu, Ga films excited by 337 nm wavelength exhibits UV (380 nm) and green emission (500 nm). PL spectra at 300 and 30 K excited by 457.9 and 405 nm wavelengths consisted of two bands - the green band at 500 nm and the red band at 650 nm. Location and intensities ratio depended on the preparation conditions.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.609-609
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• 2013

나노선은 대표적인 일차원 나노구조로 높은 부피-표면적 비율과, 조절 가능한 밴드갭 에너지, 뛰어난 광학적/전기적 특성으로 인해 다양한 잠재적 응용처를 가지며, 많이 연구되고 있다. 특히 ZnO 나노선은 대표적인 광촉매로, 높은 감광성과 높은 부피-표면적 비율 등의 특징을 가지지만, 상대적으로 넓은 밴드갭 에너지 때문에 가시광선 영역을 사용하지 못하는 단점이 있다. 본 연구에서는 CuS 나노입자/ZnO 나노선 이종구조를 간단한 두 가지의 방법으로 합성하였다. ZnO 나노선은 간단한 수열합성 방법으로 합성하였고, 그 위에 CuS 나노입자를 successive ionic layer adsorption and reaction (SILAR) 방법으로 증착하였다. 합성된 나노 구조는 기존의 ZnO 구조와는 달리 가시광 영역에서도 향상된 광촉매 특성을 보였으며, 이는 ZnO와 CuS사이의 interfacial charge transfer (IFCT)에서 기인한 것이다. SEM, TEM, XRD를 통해 CuS/ZnO 이종구조의 형태와 결정구조, 구성성분을 분석할 수 있었고, Acid Orange 7의 광분해 실험을 통해 향상된 광촉매 특성을 확인 할 수 있었다.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2006.05a
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• pp.225-231
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• 2006

.고상반응법 (solid state reaction)합성된 ZnS:Mn,Cu,Cl 형광체는 약 $20^{\sim}25{\mu}m$ 의 구형이고, Cubic/hexagonal 구조를 보였다. Electroluminescent device(ELD)는 실크 스크린된 형광층(ZnS:Mn,Cu,Cl)/유전체층 ($BaTiO_3$)으로 구성되었으며, 각층은 $30^{\sim}50{\mu}m,\;50^{\sim}60{\mu}m$ 정도로 도포 하였다. 100 V-400 Hz 의 구동조건에서, ELD 의 백색 발광은 450 nm, 480 nm 픽에서 각각 $Cl_s{\to}Cu^{+}\;_{Zn},\;Cl_s{\to}Cu^{2+}\;_{Zn}$ 전이에 의해 중첩된 청색, 녹색 밴드의 발광과, 580 nm 픽에서 Mn 의 $^{4}T_1{\to}^{6}A_1$ 전이에 의한 황색 밴드의 발광으로 이루어진다. Cu 농도의 증가에 따라 450 nm 의 발광 밴드의 휘도는 감소하며 580 nm 의 발광 밴드의 휘도가 증가하였고 발광 휘도가 향상되었다. 즉, 색온도가 높은 cold white(10000 K)에서 색온도가 낮은 Warm white(3000 K) 로 변한다. 이것은 450 nm 의 발광 밴드가 580 nm 의 발광 밴드에 흡수되는 에너지 전이 (Energy transfer) 현상에 기인한다. ZnS:Mn,Cu,Cl 의 Mn 1.5 wt %, Cu 2.5 wt.% 에서 최적 발광 휘도를 보이며, 100 V-400 Hz 에서 약 $12cd/cm^2$이였다.

• Journal of the Korean institute of surface engineering
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• v.41 no.4
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• pp.169-173
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• 2008

The objective of this study is to coat the $SiO_2$ layer uniformly on the ZnS:Cu phosphors by using Sol-Gel method. From results of SEM micrographs observation, XRD and XPS analysis, it could be confirmed that $SiO_2$ layer was relatively well coated on ZnS:Cu particles. $Ag_2S$ was used as a decoding chemical to analyze the dense and uniform coating performance of $SiO_2$ layer on phosphor particles. It could be concluded that phosphors synthesized from our two step replacement method showed strong blue peak comparing to other method and rather weak green peak also. Obtained particle size of phosphors were about 20m diameter. Luminescence properties of the phosphors were examined by photoluminescence spectra at the excitation wavelength of 270 nm.