• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.06a
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• pp.23-26
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• 1998

The domain formation phenomena of {{{{ { LiLbO}_{ 3} }}}} crystals was investigated and the method for the periodic domain formation in {{{{ { LiLbO}_{ 3} }}}} single crystals during growth was proposed in this study. The strees-induced domain formation mechanism was proposed and explained. The strong piezoelectric effect of{{{{ { LiLbO}_{ 3} }}}} at elevated temperature would be the direct driving force for the inversion of the tensile component of the internal stresses can inverse the original direction of the spontaneous polarization.

• Journal of the Korean Ceramic Society
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• v.27 no.4
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• pp.536-542
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• 1990

Single crystals of YBa2Cu3O7-x have been grown in BaCuO2 flux at temperature of 125$0^{\circ}C$ and examined using XRD, EDAX and light microscopy. The YBCO crystals were grown in a cavity which was formed by the reduction of CuO and became large by the directional solidification in the crucible. The observed crystal growth habit is square planar with the c-axis normal to the plane. The surface morphology of grown crystals were growth ledges and growth sprial paterns on a (001) face.

• Journal of the Korean Ceramic Society
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• v.27 no.5
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• pp.698-701
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• 1990

The necessary conditions for the growth of high quality Bi12SiO20 single crystals by the Czochralski method have been determined. The interface of melt and crystal was transformed convex to concave above 7 rpm. For growth <001> and <111> directions, facet morphology exhibited 4-fold and 6-fold symmetry. When the crystal of <001> growth direction was broadened, minor facet {110} was developed outstandingly.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.23 no.3
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• pp.129-134
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• 2013

Sapphire wafers are used as an important substrate for the production of blue LED (light emitting diode) and the LED's performance largely depends on the quality of the sapphire single crystals. There are several crystal growth methods for sapphire crystals and Kyropoulos method is an efficient way to grow large diameter and high-quality sapphire single crystals with low dislocation density. During Kyropoulos growth, the convection of molten melt is largely influenced by the hot zone geometry such as crucible shape, heater and refractory arrangements. In this study, CFD (computational fluid dynamics) simulations were performed according to the bottom/side ratios (per unit of the crucible surface area) of heaters. And, based on the results of analysis, the molten alumina flows and remelting phenomena were analyzed.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1999.06a
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• pp.389-402
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• 1999

Single crystal of Li2Cu1-xMxO4 (M=Ni, Zn) are promising as a substrate to realize superconducting electronic devices. The distribution coefficients of Ni and Zn to the Cu site in La2CuO4 (LCO) were estimated by the zone melting technique to grow high quality single crystals of La2Cu1-xMxO4(M=Ni, Zn). The distribution coefficient value of Ni was estimated to be 4.2 and that of Zn was estimated to be 0.66, respectively. Suitable solvent compositions were determined using these values to grow single crystals by he traveling floating zone (TSFZ) method. Single crystal of LCO, La2Cu1-xMxO4(M=Ni(x=0.01, 0.02, 0.03, 0.04), Zn(x=0.01, 0.02, 0.03) of high homogeneity were grown. The behaviors of the magnetization of these as-grown crystals do not indicate superconductivity except LCO. Ni or Zn substitution can make LCO non superconductor. This fact suggest that single crystals substituted by Ni or Zn are useful as substrate crystals.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.17-17
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• 2009

We report the invention of a direct growth method termed On-Film Formation of Nanowire (OFF-ON) for making high-quality single-crystal nanowires, i.e. Bi and $Bi_2Te_3$, without the use of conventional templates, catalysts, or starting materials. We have used the OFF-ON technique to grow single crystal semi-metallic Bi and compound semiconductor $Bi_2Te_3$ nanowires from sputtered Bi and BiTe films after thermal annealing, respectively. The mechanism for nanowire growth is stress-induced mass flow along grain boundaries in the polycrystalline films. OFF-ON is a simple but powerful method for growing perfect single-crystal semi-metallic and compound semiconductor nanowires of high aspect ratio with high crystallinity that distinguishes it from other competitive growth approaches that have been developed to date. Our results suggest that Bi and $Bi_2Te_3$ nanowires grown by OFF-ON can be an ideal material system for exploring their unique thermoelectric properties due to their high-quality single crystalline and high conductivity, which have consequence and relevance for high-efficiency thermoelectric devices.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.4
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• pp.129-134
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• 2005

A numerical analysis was performed on magnetic field effects of silicon melt motion in Czochralski crystal puller. The turbulent modeling was used to simulate the transport phenomena in 18' single crystal growing process. For small crucible angular velocity, the natural convection is dominant. As the crucible angular velocity is increased, the forced convection is increased and the distribution of temperature profiles is broadened. The cusp magnetic field reduces effectively the natural and forced convection near the crucible and the temperature profiles of the silicon fluids is similar in the case of conduction.

• Journal of the Korean Ceramic Society
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• v.29 no.9
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• pp.689-694
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• 1992

Strontium Titanate single crystal is grown by Verneuil method. Feed materials were prepared by coprecipitation method which started with Sr(NO3)2 and TiCl4. SrTiO3 can not be grown from feed materials having the stoichiometric components due to volatilization of SrO, when the powder added more 3 wt% SrO used, the crystal can be grown. Growth conditions that the pressure of oxygen and hydrogen gas was 5 psi, the flow rate of oxygen and hydrogen was 7.3 and 30ι/min respectively, the growth rate was 20 mm/hr were optimum. The grown single crystal has the diameter of 10~15 mm and its length is 30~40 mm. The grown crystal was deep brown color and somewhat transparent. The color of grown crystal was lightened after annealing.

• Current Photovoltaic Research
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• v.8 no.1
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• pp.17-26
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• 2020

It is clear that monocrystalline Silicon (Si) ingots are the key raw material for semiconductors devices. In the present industries markets, most of monocrystalline Silicon (Si) ingots are made by Czochralski Process due to their advantages with low production cost and the big crystal diameters in comparison with other manufacturing process such as Float-Zone technique. However, the disadvantage of Czochralski Process is the presence of impurities such as oxygen or carbon from the quartz and graphite crucible which later will resulted in defects and then lowering the efficiency of Si wafer. The heat transfer plays an important role in the formation of Si ingots. However, the heat transfer generates convection in Si molten state which induces the defects in Si crystal. In this study, a crystal growth simulation software was used to optimize the Si crystal growth process. The furnace and system design were modified. The results showed the melt-crystal interface shape can affect the Si crystal growth rate and defect points. In this study, the defect points and desired interface shape were controlled by specific crystal growth rate condition.

• 한국초전도학회:학술대회논문집
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• v.12
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• pp.8-8
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• 2002