• Journal of the Korean Crystal Growth and Crystal Technology
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• v.13 no.5
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• pp.254-259
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• 2003

In the fabrication process of transparent conducting thin films of the ATO (antimony-doped tin oxide) on a soda lime glass substrate by a sol-gel dip coating method, the effects of the $SiO_2$ buffer layer formed on the substrate and $N_2$ annealing treatment were investigated by XPS (X-ray photoelectron spectroscopy) analysis. Optical transmittance and electrical resistivity of the 400 nm-thick ATO thin films which were deposited on $SiO_2$ buffer layer/soda lime glass and then annealed under nitrogen atmosphere were 84 % and $5.0\times 10^{-3}\Omega \textrm{cm}$ respectively. The XPS analysis confirmed that a $SiO_2$ buffer layer inhibited Na ion diffusion from the substrate, resulting in prohibiting the formation of a secondary phase such as $Na_2SnO_3$ and SnO and increasing Sb ion concentration and ratio of $Sb^{5+}/Sb^{3+}$ in the film. And it was also found that $N_2$ annealing treatment leads to the reduction of $Sn^{4+}$as well as $Sb^{5+}$ however the reduction of $Sn^{4+}$ is more effective and therefore consequently results in decrease in the electrical resistivity to produce an excellent electrical properties of the film.

• Journal of the Korean Ceramic Society
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• v.29 no.10
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• pp.822-826
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• 1992

SiO2 doped sapphire single crystals were grown by Verneuil method using feed material which prepared by adding SiO2 in Al2O3. Crystal growing were attempted with varing doping amount of SiO2 from 0.01 to 1.0 wt% and when the doping amount of SiO2 were 0.01~0.04 wt%, single crystals could be attained. Starting materials for feed powder were 99.99% purity alumina and extra pure SiO2 powder. Mixing these two materials by wet milling for 24 hours and drying the mixture and then was calcined at 900~110$0^{\circ}C$ for 2~4 hours. The grown crystals had yellowish color and were somewhat transparent. During growing process the flow range of oxygen was 5~7.5ι/min and of hydrogen was 13~25ι/min, the average growth rate was 7.0~11 mm/hr. The pressure of gases were fixed at 5psi. The color of crystal was appeared and mechanical property of sapphire was developed by doping of SiO2.

• Proceedings of the Materials Research Society of Korea Conference
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• 1993.05a
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• pp.120-121
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• 1993

• Korean Journal of Materials Research
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• v.28 no.8
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• pp.474-477
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• 2018

$Ca_3MgSi_2O_8:Eu^{2+}$(x = 0.003, 0.005, 0.007, 0.01, 0.03 mol) white phosphors for Light Emitting Diodes(LED) are synthesized with different concentrations of $Eu^{2+}$ ions using a solid state reaction method. The crystal structures, surface and optical properties of the phosphors are investigated using X-Ray Diffraction(XRD), Scanning Electron Microscope(SEM) and photoluminescence(PL). The X-Ray Diffraction results reveals that the crystal structure of the $Ca_3MgSi_2O_8:Eu^{2+}$ is a monoclinic system. The particle size of $Ca_3MgSi_2O_8:Eu^{2+}$ white phosphors is about $1{\sim}5{\mu}m$, as confirmed by SEM images. The maximum emission spectra of the phosphors are observed at 0.01 mol $Eu^{2+}$ concentration. The decrease in PL intensity in the $Ca_3MgSi_2O_8:Eu^{2+}$ white phosphors with $Eu^{2+}$ concentration is interpreted by concentration quenching. The International Commission on Illumination(CIE) coordinate of 0.01 mol Eu doped $Ca_3MgSi_2O_8$ is X = 0.2136, Y = 0.3771.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.4
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• pp.558-563
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• 1996

Fracture strength of $Si_{3}N_{4}/20$ vol% SiC nanocomposites with fifferent sintering additives was measured. Strength of nanocomposites with 6 wt% $Y_{2}O_{3}$ and 2 wt% $Al_{2}O_{3}$ as sintering additives was higher at room temperature but significant strength degradation at elevated temperature was occured due to the softening of grain boundary phase. Fracture strength of 8 wt% $Y_{2}O_{3}$ doped sample was higher than that of $Al_{2}O_{3}$ added sample at $1400^{\circ}C$. The retention of high temperature strength in 8 wt% $Y_{2}O_{3}$ doped sample can be attributed to high softening temperature and crystallization of grain boundary glassy phase.

• Journal of Korean Vacuum Science & Technology
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• v.2 no.1
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• pp.25-31
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• 1998

The reliability of fluorine doped silicon oxide (SiOF) films for intermetal dielectrics in multilevel interconnections of ultra-large scale integrated circuits (ULSIs) is investigated. SiOF films were deposited by electron cyclotron resonance plasma-enhanced chemical vapor deposition (ECRPECVD) using H-free source gases, i.e., SiF4 and O2. The effect of post plasma treatment on the moisture absorption and dielectric properties of SiOF films was carried out I terms of air exposure time, The reliability test of Cu/TiN/SiOF/Fi specimen was carried out in terms of temperature by rapid thermal annealing (RTA) in N2 ambient. After O2 plasma treatment,, no appreciable peak directly related to moisture absorption was detected. The capacitance-voltage (C-V) characteristics of the O2 plasma treated SiOF film showed that the film remained to hold the sound dielectric properties even after boiling treatment. The Cu/TiN/SiOF/Si system was found to be reliable up to $600^{\circ}C$.

• Ceramist
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• v.10 no.3
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• pp.28-33
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• 2007

The structural and optical properties of Ni-doped transparent glass-ceramics are reviewed. The quantum efficiencies of ceramics were examined to explore suitable crystalline phase for Ni-doping in glass-ceramics. Inverse spinel $LiGa_5O_8$ have the quantum efficiency of almost 100 % at room temperature. Transparent glass ceramics containing $LiGa_5O_8$ was successfully synthesized by heat treatment of $Li_2O-Ga_2-O_3-SiO_2-NiO$ glass. Most of $Ni^{2+}$ ions in glass-ceramic were incorporated into $LiGa_5O_8$ nanocrystals. The near-infrared emission covering from the O-band to L-band (1260-1625 nm) was observed from the Ni-doped $Li_2O-Ga_2O_3-SiO_2$ glass-ceramic though it was not observed from the as-cast glass. The lifetime of the emission was about $580\;{\mu}sec$ even at 300K. The emission quantum efficiency was evaluated as about 10 % that is enough high for practical usage as gain media of optical fiber amplifiers. The figure of merit (the product of the stimulated emission cross section and lifetime) was as high as that of rare-earth-doped glasses. The broad bandwidth, high quantum efficiency and high figure of merit show that transparent glass-ceramics containing $Ni^{2+}:LiGa_5O_8$ nanocrystals are promising candidates as novel ultra-broadband gain media.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.11
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• pp.2385-2390
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• 2009

N-doped ZnO thin films with c-axis preferred orientation were prepared on p-Si(100) wafers, using an RF magnetron sputter deposition. For ZnO deposition, $N_2O$ gas was employed as a dopant source and various deposition conditions such as $N_2O$ gas fraction and RF power were applied. The depth pofiles of the nitrogen [N] atoms incorporated into the ZnO thin films were investigated by Auger Electron Spectroscopy(AES) and the nano-scale structural characteristics of the N-doped ZnO thin films were also investigated by a scanning electron microscope (SEM) technique.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.640-640
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• 2013

본 연구에서는 유리 기판과 Si 기판에 Ag-doped ZnO 나노로드를 수열합성법을 이용하여 성장하였다. ZnO는 UV 영역에서 exciton 발광을 하며, 가시광선에서도 발광을 하는 것으로 알려져 있다. 그리고 Ag 금속은 입자형태로 ZnO 박막에 도포되었을 때 UV영역의 발광 세기를 강화시킨다는 사실이 알려져 있다. 이러한 내용을 바탕으로 ZnO 나노로드 합성 용액에 Ag powder의 양을 변화시켜 첨가하고, 유리와 Si기판을 넣고 80도에서 30분간 성장하였다. XRD, XPS를 통해 구조적 특성 변화를 보았고 SEM을 통해 나노로드의 형태를 확인하였다. 또한 PL, 투과도 측정을 통해 Ag 도핑에 따른 광학적 특성 변화를 확인하였다. SEM 측정으로 샘플의 단면을 확인한 결과 Ag 도핑 농도에 따른 차이가 거의 없음을 알았다. ZnO 나노로드가 성장된 유리 기판은 본래의 유리기판보다 투과도가 높았으며, Ag를 많이 첨가할수록 투과도가 낮아졌다.

• Korean Journal of Materials Research
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• v.24 no.1
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• pp.43-47
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• 2014

NiO-doped hibonite pigments were synthesized by the solid state method to get stabilized blue color pigment in both oxidation and reduction atmospheres. Optimum substitution condition with NiO for hibonite blue pigment was investigated. Experimental results were comparable to those of previous cobalt-minimization studies performed with other phosphate- or oxide-based cobalt-containing ceramic pigments (having olivine ($Co_2SiO_4$), spinel ($CoAl_2O_4$), or with co-doped willemite ($(Co,Zn)_2SiO_4$) structures). Composition was designed varying the NiO molar ratio increasing with $SnO_2$. The optimum substitution content is 0.93 mole NiO with 0.75mole $SnO_2$. The characteristics of the synthesized pigment were analyzed by XRD, Raman spectroscopy, SEM, and UV-vis. Synthesized pigment was applied to a lime-barium glaze with 10 wt% each and fired at an oxidation atmosphere of $1250^{\circ}C/1h$ and a reducing atmosphere $1240^{\circ}C/1h$. Blue color was obtained with $L^*a^*b^*$ values at 43.39, -6.78, -18.20 under a reducing atmosphere and 41.66, -6.36, -14.7 under and oxidation atmosphere, respectively.