• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.34-35
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• 2009

We have studied the electrical and optical of organic light-emitting diodes depending on hole size of crucible boat using BCP materials. The thickness of TPD, $Alq_3$ and BCP was manufactured 40 nm, 60 nm and 5 nm under a base pressure of $5\times10^{-6}$ Torr using at thermal evaporation, respectively. In order to investigate the optimal surface roughness of BCP, the BCP was thermally evaporated to be 0.8 nun, 1.0 mm, 1.2 mm and 1.5 mm as a hole size of crucible boat, respectively. As the experimental results, we found that the luminous efficiency and the external quantum efficiency of the device is superior to others when hole size of crucible boat using BCP is 1.2 mm. Also, compared to the ones from the devices having the hole size of crucible boat is 1.0 mm and 1.5mm layer, the external quantum efficiency were improved by 2.5 and 2.4 times.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.6
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• pp.569-574
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• 2008

In the device structure of ITO/tris(8-hydroxyquinoline) aluminum ($Alq_3$)/Al device, we investigated the efficiency improvement of organic light-emitting diodes (OLEDs) depending on the hole-size of crucible boat. The device was manufactured using a thermal evaporation under the base pressure of $5{\times}10^{-6}\;Torr$. The $Alq_3$ organics were evaporated to be 100 nm thick at a deposition rate of $1.5\AA/s$, and in order to investigate the optimal surface roughness of $Alq_3$, the $Alq_3$ was thermally evaporated to be 0.8 mm, 1.0 mm, and 1.5 mm as a hole-size of the boat, respectively. We found that luminance and external quantum efficiency are superior when the hole-size of the boat is 1.0 mm. The external quantum efficiency of the device made with the hole-size of 1.0 mm boat were improved by a factor of ten compared to the devices made with the hole-size of non boat.

• Journal of the Korean Ceramic Society
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• v.31 no.1
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• pp.39-46
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• 1994

LiTaO3 single crystals were growth without cracking using Pt-Rh crucible and Ir crucible. The starting composition to get the melt of congruent melting composition, which has been dependent upon the experimental procedure, was taken after fixing the total growing process by the result of preliminary experiments. The Rh contamination from the Pt-Rh crucible was to be neglected if the crystal had been grown under inert atmosphere, which resulted in the crystal color being slightly yellow. This color was decolored after 24 hour's annealing at 1200℃ under air atmosphere. The optimum conditions for the crystal growing and the diameter control were so dependent upon the crucible material in spite of using the crucible of the same size. The liquid-solid interface of LiTaO3 crystal of 1" diameter has been flat if the rotation speed was 45rpm.

• Korean Chemical Engineering Research
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• v.49 no.4
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• pp.432-437
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• 2011

Recently, industry needs a new design of Czochralski(Cz) process for higher productivity with reasonable energy consumption. In this study, we carried out computational simulations for finding out a new optimal design of Cz process with variables which can be applied in real industry such as location of heater, shape of shield and crucible size. Objective process was Cz process which can be produced 8 inch diameter Si ingot for solar cell and we acquired an optimal design for higher productivity, low power consumption with stable production condition. For higher productivity we also change the crucible diameter from 22 inches to 24 inches with changing insulation thickness only because the process housing size could not be changed in industry.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.22 no.1
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• pp.74-80
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• 2009

In the structure of ITO/N,N'-diphenyl-N,N' bis (3-methylphenyl)-1,1'-biphenyl-4,4'-diamine(TPD)/tris (8-hydroxyquinoline)aluminum($Alq_3$)/Al device, we studied the efficiency improvement of organic light-emitting diodes due to variation of deposition rate of hole transport layer (TPD) materials using hole-size of crucible boat. The thickness of TPD and $Alq_3$ was manufactured 40 nm, 60 nm, respectively under a base pressure of $5{\times}10^{-6}$ Torr using a thermal evaporation. The $Alq_3$ used for an electron-transport and emissive layer were evaporated to be at a deposition rate of $2.5\;{\AA}/s$. When the deposition rate of TPD increased from 1.5 to $3.0\;{\AA}/s$, we studied the efficiency improvement of TPD using the hole-size of crucible is 1.0 mm. When the deposition rate of TPD is $2.5\;{\AA}/s$, we found that the average roughness is rather smoother, the luminous efficiency the external quantum efficiency is superior to the others. Compared to the two from the devices made with the deposition rate of TPD is $2.0\;{\AA}/s$ and $3.0\;{\AA}/s$, the external quantum efficiency was improved by four-times and two-times, respectively.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.11a
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• pp.29-30
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• 2007

In a device structure of ITO/tris(8-hydroxyquinoline) aluminum $(Alq_3)$/Al device, We investigated an the electrical characteristics of Organic Light-Emitting Diodes (OLEDs) depending on the hole-size of boat. The device was manufactured using a thermal evaporation under a base pressure of $5{\times}10^{-6}$ [Torr]. The $Alq_3$ organics were evaporated to be 100 [nm] thick at a deposition rate of $1.5[{\AA}/s]$, and in order to investigate the optimal surface roughness of $Alq_3$, the $Alq_3$ was thermally evaporated to be 0.8 [mm], 1.0 [mm], 1.5 [mm], and 3.0 [mm] as a hole-size of the boat respectively. We found that when the hole-size of the boat is 1.0 [mm], luminance and external quantum efficiency are superior.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.32 no.3
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• pp.115-120
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• 2022

A brown ring (hereinafter referred to as BR) on the inner surface of a quartz glass crucible used in the manufacturing process of a silicon ingot for semiconductor wafers was studied. BR is 20~30 ㎛ in size and has an asymmetric brown ring shape. The size and distribution of BR were different depending on the crucible location, and the size and distribution of BR were the largest and most abundant in the round part with the highest crucible temperature during Si ingot growth. BR contains cristobalite, which has a higher coefficient of thermal expansion than quartz glass, so it is considered that surface cracks appear. The color development of BR and pin holes are presumed to be due to oxygen vacancies.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1327-1328
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• 2007

A base structure of device was made to be ITO/tris(8-hydroxyquinoline) aluminum ($Alq_3$)/Al and the $Alq_3$ organics were evaporated to be 100nm thick at a deposition rate of $1.5\;{\AA}/s$. In order to investigate the optimal surface roughness of $Alq_3$, the $Alq_3$ was thermally evaporated to be 0.8 mm, 1.0 mm, 1.5 mm 2.0 mm and 3.0 mm as a hole-size of the crucible, respectively. When the hole-size of the crucible is 1.0 mm, we found that when the hole-size of the crucible is 1.0 mm, the electrical properties are superior to the others.

• Journal of the Korean Ceramic Society
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• v.30 no.4
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• pp.309-315
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• 1993

Gas pressure sintering is a promising process in various densification methods of high strength Si3N4 ceramics. Environmental influences on gas pressure sintering of Si3N4 was investigated with the variationof packing powder, specimen container and N2 gas pressure. The specimens had higher density, larger weight loss and inhomogeneous color in graphite specimen container than in SN26 crucible. The variations of sintering densities in various packing powders (Si3N4, SN26, AlN, BN) were very small but SiC powder was synthesised in graphite crucible with Si3N4 packing powder, aluminium oxynitride compounds were synthesised in SN26 crucible with AlN packing power. Also N2 gas pressure over 20kg/$\textrm{cm}^2$ reduced the densification of Si3N4 in one step-gas pressure sintering. As the result of two step-gas pressure sintering at 700kg/$\textrm{cm}^2$ for 15min., relative density of 99.9% and 3-point bending strength of 1090MPa and dense microstructure of 3~4${\mu}{\textrm}{m}$ grain size were obtained.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.09a
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• pp.113-116
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• 1998

A numerical study was performed on the fluid flow in the melt of the cold model for Czochralski growth system. The fluid flow in the melt of Woods metal with crucible diameter of 20cm was calculated using a three dimensional finite difference method. Since the crucible size is large, fully turbulent model as well as laminar model was used in the calculation. The effects of crucible rotation rate, crystal rotation rate and wall temperature difference on the velocity and temperature distribution were also investigated. For the purpose of verifying the results of calculation, a cold model experiment using Woods metal was also conducted and the velocity distribution in the melt of the model was measured.