• Journal of the Korean institute of surface engineering
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• v.51 no.4
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• pp.243-248
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• 2018

All solid state thin film batteries with two types of cell structure, Pt / $LiCoO_2$ / LiPON / Cu and Pt / $LiCoO_2$ / LiPON / $LiCoO_2$ / Cu, are prepared and their electrochemical performances are investigated to evaluate the effect of $LiCoO_2$ interlayer at the interface of LiPON / Cu. The crystallinity of the deposited $LiCoO_2$ thin films is confirmed by XRD and Raman analysis. The crystalline $LiCoO_2$ cathode thin film is obtained and $LiCoO_2$ as the interlayer appears to be amorphous. The surface morphology of Cu current collector after cycling of the batteries is observed by AFM. The presence of a 10 nm-thick layer of $LiCoO_2$ at the interface of LiPON / Cu enhances the interfacial adhesion and reduces the interfacial resistance. As a result, Li plating / stripping at the interface of LiPON / Cu during charge/discharge reaction takes place more uniformly on Cu current collector, while without the interlayer of $LiCoO_2$ at the interface of LiPON / Cu, the Li plating / stripping is localized on current collector. The thin film batteries with the interlayer of $LiCoO_2$ at the interface of LiPON / Cu exhibits enhanced initial coulombic efficiency, reversible capacity and cycling stability. The thickness of the anode current collector Cu also appears to be crucial for electrochemical performances of all solid state thin film batteries.

• Proceedings of the Korean Vacuum Society Conference
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• 2016.02a
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• pp.399.1-399.1
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• 2016

p-type 반도체 물질로 알려진 $Cu_2O$에 Li 이온을 doping하면 Cu 이온 자리에 Li이온이 치환되어 p-type의 특성이 더욱 강하게 나타내는 것으로 알려져 있다. 이에 본 연구에서는 RF magnetron sputtering방법으로 성막한 p-type형 $Li:Cu_2O$박막의 특성을 연구하고 이를 $Li:Cu_2O-ZnO$ pn 접합 유연 나노제너레이터에 적용하였다. $Li:Cu_2O$ 성막시 $O_2$ 분압을 변수로 100nm 두께의 $Li:Cu_2O$ 박막을 성막하여 전기적, 광학적, 구조적, 표면 특성을 분석하였다. Hall measurement 측정 결과 $Li:Cu_2O$ 박막은 정공을 Major Carrier로 갖는 p-type 반도체임을 확인하였고, $O_2$의 분압이 증가할수록 Mobility 및 Carrier Concentration이 증가함을 확인하였다. 최적조건에서 광학적 투과도는 약 45%를 보였으며, 투과도를 통해 계산한 band gap은 약 2.03eV로써 일반적인 산화물 반도체의 작은 밴드갭을 가지고 있음을 알 수 있었다. 또한 Ellipsometer분석을 통해 $Ar:O_2$ 비가 $Li:Cu_2O$ 굴절률 및 흡광도에 미치는 영향을 연구하였으며, FE-SEM(Field Emission Scanning Electron Microscope)을 통해 표면을 분석하였다. 또한 XRD(X-ray diffractometer), TEM(Transmission Electron Microscope) 분석을 통하여 상온에서 성막한 $Li:Cu_2O$ 박막의 미세구조를 연구하였다. UPS(Ultraviolet Photoelectron Spectroscopy) 분석을 통해 일함수를 측정하였다. 이렇게 제작된 p 타입 $Li:Cu_2O$ 박막을 이용하여 $Li:Cu_2O-ZnO$ pn 접합을 구현하고 이를 이용해 유연 나노제너레이터를 제작하였다. 다양한 특성 분석을 통해p-type을 이용한 산화물 박막 기반 유연 나노 제너레이터 특성 향상 메커니즘을 제시하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.3
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• pp.258-263
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• 2000

Effect of microwave heat-treatment processing on the electrical conductivity and crystallization behavior for the $Li_2O-2SiO_2$-xCuO glasses with various CuO contents was compared with that of conventional heat-treatment processing. The electrical conductivities of samples heat-treated at $500^{\circ}C$ by different heat-treatment processing were increased with increasing CuO content and higher electrical conductivities were obtained from microwave heat-treated samples. From the result of XRD analyses, microwave heat-treatment processing enhanced the degree of crystallization in the formation of $Li_2Si_2O_5, Li_2Cu_5$($Si_2O_7)_2$, and $Li_2Cu_2O_3$ crystalline phases. The electrical conductivities of $Li_2O-2SiO_2$-1.3CuO (30 mol% CuO) glass heat-treated at $500^{\circ}C$ for 30 min under conventional and microwave heat-treatment processing were $0.11{\times}10^{-4}(\Omega \textrm {cm})^{-1}$ and $0.68{\times}10^{-4}(\Omega \textrm {cm})^{-1}$ at room temperature, respectively. It was speculated that microwave energy enhanced the degree of crystallization and increased electrical conductivity in the samples.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.713-716
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• 2001

In many papers, the electrochemical analysis of LiMn$_2$O$_4$shows the transition results of Mn$^{3+}$ ion. Charge ordering is accompanied by simultaneous orbital ordering due to the Jahn-Teller effect in Mnl$^{3+}$ ions. To analyze the cycle performance of LiMn$_{2-x}$Cu$_{x}$ O$_4$as the cathode of 4 V class lithium secondary batteries, XRD, TGA analysis were conducted. Although the cycle performance of the LiMn$_{2-x}$Cu$_{x}$ O$_4$was improved from pure LiMn$_2$O$_4$, the discharge capacity was significantly lower than LiCoO$_2$. In this paper, We study the Electrochemical characterization and enhanced stability of Cu-doped spinels in the LiMn$_{2-x}$Cu$_{x}$ O$_4$upon initial cycling.l cycling.

• Bulletin of the Korean Chemical Society
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• v.11 no.6
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• pp.564-567
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• 1990

A lithiated compound $Li_{0.1}Pr^{3+}Ba_2Cu_3O_y$ has been successfully prepared by electrochemical method, which is achieved with a two electrode cell of the type: Metal(Li)/($Li^+\;,\;ClO_4^-$) + propylene carbonate/$PrBa_2Cu_3O_y$. All Pr ions in the lithiated compound are stabilized with a trivalent state as the other rare earths (Ⅲ) substituted in the 90K superconductor lattice ($Y_{1-x}Ln_x^-Ba_2Cu_3O_{7-{\delta}}$). Powder X-ray diffraction analysis shows that both compounds, $PrBa_2Cu_3O_y$ and $Li_{0.1}PrBa_2Cu_3O_y$ are isostructural with the 90 K superconductor, ($YBa_2Cu_3O_{7-{\delta}}$), nevertheless both of them are non-metallic and also non-superconducting down to 10 K. Magnetic susceptibility ${\chi}$ vs. temperature data indicate that Curie contribution from the magnetic ions (Pr and Cu) is weakened on the one hand, but on the other hand temperature-independent part of susceptibility ${\chi}_o$ increases depending upon the rate of lithium intercalation in $PrBa_2Cu_3O_y$ lattice.

• Journal of the Korean Magnetics Society
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• v.16 no.1
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• pp.34-39
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• 2006

Pure and Fe-doped CuO thin-film and powder samples were prepared using a sol-gel method. Undoped CuO films exhibited monoclinic structure and p-type electrical conductivity $(\~10^{-2}\;{\Omega^{-1}\;cm^{-1}$ due to copper deficiency. On the other hand, CuO: Fe films were found to be insulating and Li doping on the films led to a restoration of p-type conductivity and a ferromagnetic hysteresis behaviour at room temperature. The observed properties far the CuO : Fe, Li films can be explained in terms of hole creation by substitution of $Li^+$ for $Cu^{2+}$ sites and mediation of long-range interactions between $Fe^{3+}$ ions by the $Li^+$-induced defect states. CuO: Fe powders exhibited a ferromagnetism at room temperature with its strength being dependent on post-annealing temperature. Mossbauer measurements on the CuO: Fe films and powders revealed that the octahedral $Cu^{2+}$ sites are mostly substituted by $Fe^{3+}$ ions.

• Proceedings of the Korean Magnestics Society Conference
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• 1998.05a
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• pp.68-69
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• 1998

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.5
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• pp.995-999
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• 2007

The lead zirconate titanate (PZT) powders were synthesized to make the piezoelectric ceramics in low temperature as low as $900^{\circ}C$. To investigate the influence of additives on sintering of PZT, two kinds of sintering aids were made as follows; $wB_2O_3-xBi_2O_3-zCuO$and LiBiO2-CuO. The sintering aid, $1{\sim}3$ wt.% $LiBiO_2-CuO$, was added into these PZT powders and the specimens were fired at temperature in the range of $800{\sim}1200^{\circ}C$. The highest density was shown in the specimen with 1 wt.% $LiBiO_2-CuO$ as additive at temperature of $900^{\circ}C$. The sintered specimen were analyzed by X-ray diffraction(XRD) and scanning electron microscopy (SEM) was utilized to observe the microstructure, especially the densified morphology of specimens. In the XRD pattern, the well-crystallized PZT phase could be obtained in consequence of firing at $900^{\circ}C$. The scanning electron microscopy(SEM) was utilized to observe the structure of specimens after firing at $900^{\circ}C$. The densified perovskite structure of $PbZrTiO_3$ could be obtained by sintering at temperature as low as $900^{\circ}C$. The high sinterability of PZT ceramics was attributed to the low formation temperature of the liquid phase of additives.

• Journal of the Korean Electrochemical Society
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• v.9 no.1
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• pp.34-39
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• 2006

Electrochemical properties of Cu foil current collector with a $Li_{0.5}La_{0.5}TiO_3$ Cu a Si thin film deposited by r.f sputtering as an anode for Li free battery were evaluated. The Cu foil current collectors were lied in and out of plasma during sputtering process. The X-ray diffraction results indicated that the as-deposited Si and $Li_{0.5}La_{0.5}TiO_3$ thin films in and out of plasma did not show any crystalline difference. The $Li_{0.5}La_{0.5}TiO_3$ film in plasma and Si film out of plasma showed better cyclability since crystalline $Li_{0.5}La_{0.5}TiO_3$ has much higher ionic conductivity and crystalline Si film is much sensitive far volume change during charge-discharge process. These results suggested that the deposition of amorphous Si on Cu foil current collector is much better for fabrication of Li free battery and it can be useful for the unique battery with a cycling number constraint of below 10.

• Progress in Superconductivity and Cryogenics
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• v.1 no.1
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• pp.7-14
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• 1999

Wekk oriented $Bi_{2} Sr_{2} CaCu_{2} O_{8}$ suppercondcting thick films were fabricared on copper tape by LiReac-PreCu (liquid reaction between a Cu-free precousor and Cu tape) method. Cu-free precursor power which is composed of $Bi_{2}Sr_{2}Ca_{5}$ was printed on a copper tape by screen printing and was heat-treated. The speciment were partially in a molten state at the heat treatment temperature (85$0^{\circ}C$~87$0^{\circ}C$). The heat heat treatments for the reaction were performed in air or low oxygen pressure in several stages. XRD analyses of the resulting Bi2Sr2CaCu2O8 superconducting tapes show that the $Bi_{2} Sr_{2} CaCu_{2} O_{8}$ phase is dominant and a small amount of $Bi_{2} Sr_{2} Cu_{2} O_{6}$ phase is detected. Both phases are aligned in the c-axis direction.