• Journal of Surface Science and Engineering
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• v.56 no.1
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• pp.62-68
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• 2023

Silicon (Si) is considered as a promising substitute for the conventional graphite due to its high theoretical specific capacity (3579 mAh/g, Li₁₅Si₄) and proper working voltage (~0.3V vs Li⁺/Li). However, the large volume change of Si during (de)lithiation brings about severe degradation of battery performances, rendering it difficult to be applied in the practical battery directly. As a one feasible candidate of industrial Si anode, silicon monoxide (SiO_x) demonstrates great electrochemical stability with its specialized strategy, downsized Si nanocrystallites surrounded by Li⁺ inactive buffer phase (Li₂O and Li₄SiO₄). Nevertheless, SiO_x inherently has the initial irreversible capacity and poor electrical conductivity. To overcome those issues, conformal carbon coating has been performed on SiO_x utilizing ethylbenzene as the carbon precursor of chemical vapor deposition (CVD). Through various characterizations, it is confirmed that the carbon is homogeneously coated on the surface of SiO_x. Accordingly, the carbon-coated SiOx from CVD using ethylbenzene demonstrates 73% of the first cycle efficiency and great cycle life (88.1% capacity retention at 50th cycle). This work provides a promising synthetic route of the uniform and scalable carbon coating on Si anode for high-energy density.

• Korean Journal of Crystallography
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• v.15 no.1
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• pp.18-23
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• 2004

In order to find the optical properties of CdSe thin film and CdSe nanostructure, the following experiments were performed: the CdSe wurtzite nanostructure was made by using 99.99% CdSe (Aldrich) powder with the $SiO_x$ substrates and the $AlO_x$ membranes in $7{\times}10^{-6}$ torr vacuum. (The average vacuum coating speed being 1 ${\AA}$/sec). The calculations obtained were about 200 nm diameter of nanotubes on the $AlO_x$ membranes and a crystallite size of about 2 nm on the $SiO_x$ substrates. These results were verified through the Scanning Electron Microscopy (SEM) analysis, thin film X-ray diffraction analysis and emission spectroscopy.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.223-228
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• 1998

Glass films of $SiO_2-TiO_2-M_xO_y$ (M = Co, Cr or Cu) have been prepared on soda-lime-silica slide glasses by the chemical solution method using a spin-coating technique. Commercially available tetraethyl orthosilicate, titanium trichloride, and cobalt-, chromium- and copper-nitrates were used as starting materials. No crystalline segregations of $Co_3O_4$, $Cr_2O_3$ and CuO were observed by X-ray diffraction ${\theta}-2{\theta}$ scans. From the optical transmission analysis, cobalt existed as $ Co^{2+}$ in tetrahedral coordination, chromium as $Cr^{6+}$ in tetrahedral symmetry and copper as $Cu^{2+}$ in octahedral coordination. Films with a crack-free and no texture exhibited homogeneous interfaces between the films and the substrates along the cross-section.

• Journal of the Korean Ceramic Society
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• v.42 no.3 s.274
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• pp.145-149
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• 2005

[ $Eu^{2+}$ ]-activated barium magnesium silicate phosphor, $(Ba,Ca)_{3}MgSi_{2}O_{8}:Eu_{x}$, has been known to emit blue-green light. In this study we report the manufacturing processes for producing either pure green or pure blue light-emitting phosphor from the same composition of $Ba_{2-x}Ca_{2}CaMgSi_{2}O_{8}:Eu_{x}$ (0 < x < 1) by controlling heat treatment conditions. Green light emitting phosphor of $Ba_{1.9}CaMgSi_{2}O_{8}:Eu_{0.1}$ can be produced under the sample preparation condition of highly reducing atmosphere of $23\%\;H_2/77\%\;N_2$, while blue or blue-green light emitting phosphor under reducing atmosphere of $5\~20\%\;H_2\;/\;95\~80\%$ N_2. The green light-emitting phosphors are prepared in two steps: firing at $800\~1000^{\circ}C$ for $2\~5$ h in air then at $1100\~1350^{\circ}C$ for 2-5 h under reducing atmo­sphere $23\%$ $H_2/77\%\;N_2$. The excitation spectrum of the green light-emitting phosphor shows a broadband of $300\~410$ nm. The emission spectrum has a maximum intensity at the wavelength of about 501 nm. The CIE value of green light emission is (0.162, 0.528). The pure blue light-emitting phosphors can be produced using the $Ba{2_x}CaMgSi_{2}O_{8}:Eu_{x}$ by introducing additional firing step at $1150\~1300^{\circ}C$ in air before the final reducing treatment. The XRD analysis shows that the green light-emitting phosphor mainly consisted of $Ba_{1.31}Ca_{0.69}SiO_{4}$ (JCPDS $\#$ 36-1449) and other minor phases i.e., $MgSiO_3$ (JCPDS $\#$ 22-0714) and $Ca_{2}BaMgSi_{2}O_{8}$ (JCPDS $\#$ 31-0128). The blue light-emitting phosphor mainly consisted of $Ca_{2}BaMgSi_{2}O_{8}$ phase.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.9
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• pp.623-627
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• 1999

We report a new in-situ fluorine passivation method without in implantation by employing excimer laser annealing of $SiO_{x}F_{y}$/a-Si structure and its effects on p-channel poly-Si TFTs. The proposed method doesn't require any additional annealing step and is a low temperature process because fluorine passivation is simultaneous with excimer-laser-induced crystallization. A in-situ fluorine passivation by the proposed method was verified form XPS analysis and conductivity measurement. From experimental results, it has been shown that the proposed method is effective to improve the electrical characteristics, specially field-effect mobility, and the electrical stability of p-channel poly-Si TFTs. The improvement id due to fluorine passivation, which reduces the trap state density and forms the strong Si-F bonds in poly-Si channel and $SiO_2/poly-Si$ interface. From these results, the high performance poly-Si TFTs canbe obtained by employing the excimer-laser-induced fluorine passivation method.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.166-166
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• 2013

Mesoporous $SiO_2$-supported Ni catalysts (Ni/$SiO_2$ and Ni/$TiO_2$/$SiO_2$) were fabricated by atomic layer deposition (ALD), and their catalytic activity and stability were investigated in carbon dioxide reforming of methane (CRM) reaction at $800^{\circ}C$ The Ni/$SiO_2$ catalysts showed high stability as a result of confinement of Ni particles with a mean size of ~10 nm within the pores of $SiO_2$ support. Besides, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and transmission electron microscopy (TEM) results showed that the Ni nanoparticles were partially buried inside the $SiO_2$ support. The strong interaction between Ni and the $SiO_2$ support could also be advantageous for long-term stability of the catalyst. In case of the Ni/$TiO_2$/$SiO_2$ catalyst, it was found that the catalytic activity of 10 nm-sized Ni nanoparticles was not much influenced by $TiO_2$ addition.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.135-136
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• 2008

이 실험에서는 비휘발성 메모리에서의 블로킹 층으로 $SiN_x$ 박막을 사용하였다. ELA (poly-Si) 기판위에 $SiO_xN_y$ 박막을 성장하기 전에 BHF를 이용해 자연 산화막을 제거하였다. 터널 층을 위해 2.7nm두께의 $SiO_xN_y$를 ICP-CVD 장비를 이용해 유리기판위에 증착하였다. 다음으로 $SiH_4/H_2$기체를 이용， ICP-CVD장비를 이용해 전하 저장을 위한 a-Si 박막을 증착하고, 마지막으로 a-Si층 위에 $SiN_x$ 층을 형성하였다. $SiN_x$ 박막을 형성하는데 최적의 조건을 찾기 위해 가스의 구성 비율 및 증착시간을 변화시키고 온도와 RF power도 바꿔주었다. 굴절률이 1.79 고 두께가 30 nm 인 $SiN_x$는 블로킹 층으로 사용하기 위한 것이다. 제작된 NSO-NVM 소자의 전기적 메모리 특성은 on current가 약 $10^{-5}$ A 이고 off current가 약 $5\times10^{-13}$ A로 전류 점멸비$(I_{ON}/I_{OFF})$는 약 $1\times10^7$ 이고 Swing 값은 0.53V/decade 이다. 1ms 동안의 programming/erasing 결과 약 3.5 V의 넓은 메모리 윈도우 크기를 가진다는 것을 확인할 수 있다.

• Journal of the Korean Ceramic Society
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• v.24 no.2
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• pp.155-160
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• 1987

The investigation includes the application of $ZrSiO_4-Cd(SxSe_{1-x})$stain to ceramic body. The currently developed stain was compared to the commercially available stain in applying to ceremic glaze. Two stains (currently developed and commecially available) were mixed with frits and applied to ceramic tiles. The tiles were fired at 850 to 120$0^{\circ}C$ and tested by colorimeter in X.Y.Z. axis of the wavelength ranging from 580nm to 650nm. Applicability 18 stains to ceramic body was investigated by ISCC-NBS of Munsell color nomenclature. $ZrSiO_4-Cd(SxSe_{1-x})$stain is as good as V and Pr series stain in mixing composition of frits 9 to 1. It maintains red color at 100$0^{\circ}C$ in the mixture of frits, and shows as the strong acid resistance stain.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.818-821
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• 2006

We demonstrate the vertical alignment of liquid crystal on $a-SiO_x$ film surface using the ion beam exposure. Liquid crystal can be aligned vertically by the rotational oblique evaporation of $a-SiO_x$ film. However, the electro-optic switching behavior of liquid crystal along random directions results in disclination lines. We found that we can achieve highly uniform alignment of liquid crystal without disclination lines by using the ion beam exposure. We found from XRD and XPS data that the vertical alignment can be achieved when x approaches 1.5 at the $a-SiO_x$ film surface. We have shown that the pretilt angle can be controlled by changing ion beam parameters, such as the ion beam energy, the angle of incidence, and the exposure time. We found that whether liquid crystals can be aligned vertically or homogeneously on $a-SiO_x$ film can be predicted simply by measuring the change in optical transmittance by deposition of $a-SiO_x$ thin film layers. We also have shown that a liquid crystal cell aligned vertically by the ion beam exposure exhibits the voltage-transmittance curve similar to that of a rubbed polyimide cell.

• Journal of the Korean Vacuum Society
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• v.6 no.2
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• pp.159-164
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• 1997

We have studied initial oxidation of the alkali metal(AM)/Si(111) surface using X-ray photoelectron spectroscopy(XPS) and reflection high energy electron diffraction(RHEED) at room temperature(RT) and high temperature(HT)(300~50$0^{\circ}C$). The oxidation of the Si(111)7$\times$7 surface was promoted by the adsorption of 1 momolayer(ML) AM, whereas no promotion occurred for submonolayer(<0.5 ML) adsorbed Si(111)7$\times$7 surface at RT. O Is core level spectra were measured with increasing oxygen exposure. It was found that the oxygen adsorbed on the Si(111)7$\times$7-AM surface have two different bond configuration, Si-O and Am-O, respectively. From these results, we discussed the role of AM-O bonding in the promoted oxidation. At HT(300~50$0^{\circ}C$), the AM-adsorbed surface became very inactive with the structural transformation to the 3$\times$1-AM. We present the results of the oxidation of the Si(111)3$\times$1-AM(Na, K, Cs) surface.