• Journal of the Korean Crystal Growth and Crystal Technology
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• v.5 no.1
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• pp.50-59
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• 1995

Abstract 6 H - SiC single crystal was grown by sublimation growth system which was self - designed and manufactured. In order that the SiC source might be decomposited and sublimed and deposited on the 6H - seed substrate grown by Acheson method, the temperature gradient, the growth parameters of growth temperature and pressure were operately adjusted. So we could get the optimum temperature gradient inside of the crucible. The graphite crucible with SiC powder and thermal shield componants were purified at the elevated temperature by means of Ar purging process and the source baking, then it distributed to reduce the amount of the impurities come from those parts. It was recognized that the optimum growth temperature of the crucible was$2300~2400^{\circ}C$ at the Ar atmospheric pressure of 200~400 torr, and at that moment the growth rate was 500~1000 $\mu\textrm{m}$. And then, the as- grown crystal was cut with the wafer form, the evaluation about the crystal was carried out by XRD, the optical microscopic observation and FT IR spectrum measurement.

• Proceedings of the Korea Association of Crystal Growth Conference
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• 1998.06a
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• pp.7-10
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• 1998

L-Histidine tetrafluoroborate single crystals have been grown from the aqueous solution. The profitable pH value to grow large crystals, the relative flow rate to get clear crystals, crystals habit and the orientation of the obtained crystal have been clarified. We have also demonstrated that the LHBF crystal has very high damage threshold which is potentially good for generation of the phase conjugated waves.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.20 no.2
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• pp.65-68
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• 2010

$Sr_{0.6}Ba_{0.4}Nb_2O_6$ (60SBN) and $Sr_{0.75}Ba_{0.35}Nb_2O_6$ (75SBN) single crystals were grown by Czochralski method. Growing direction was <001>, and as-grown crystals has well-developed (001) plane. Temperature- and frequency dependence of dielectric constant represent relaxor ferroelectrics. 60SBN has wider optical transmittance than 75SBN.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.17 no.3
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• pp.108-112
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• 2007

Cubic Zirconia single crystals having changeable color with light source were grown by skull melting method. Strong absorption of yellow color region light by Co and Nd and the absorption in violet color region by Fe led the color change from blue-green to red-purple with the light source from fluorescent to incandescent lamp. Color of crystals varied not only by the dopants but yttria contents and the conditions far heat treatment.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.3 no.1
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• pp.85-92
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• 1993

Large single crystals of olivine were grown by using image furnace(floating zone furnace)under controlled partial pressure of oxygen. The transparent crystals have maximum sizes 65mm in length by 7mm in diameter. When partial pressure of oxygen was decreased, the portion of secondary phases in crystals were increased so that it made crystals dark brown. The secondary phases were proved to be solid solution of Mg, Si, and Fe by electron microprobe analysis. Mg was major portion and the rest was minor.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.10 no.6
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• pp.373-377
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• 2000

For 6H-SiC single crystals which was obtained by sublimation growth (modified Lely process), the relation between the defects and the etch pits to be formed at the site of dislocations were discussed. Typical hexagonal etch pits were formed on (0001) basal plane. The similar hexagonal etch pit shapes were formed on the site of micropipe defects and it was realized that internal planar defects was formed with the same matrix crystal structure as grown crystals, through the observation of the etching morphology at those internal defects.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.15 no.6
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• pp.225-228
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• 2005

We have grown the long persistent $SrAl_2O_4:Eu^{2+},\;Dy^{3+}$ phosphor single crystal by Verneuil method. The obtained single crystals were long persistent phosphorescence peaking at ${\lambda}=520nm$ with a size of about 5 mm diameter, 55 mm length. The melting temperature of $SrAl_2O_4:Eu^{2+},\;Dy^{3+}$ measured $T_{mp}=1968^{\circ}C$. The optimum composition was $SrCO_3:Al(OH)_3:Eu_2O_3:Dy_2O_3$ = 1 : 2 : 0.015 : 0.02. Flow rate of $H_2:O_2$ is about 4 : 1. Growthing rate is about 5 mm/hr. The spectra of the phosphorescence from the crystals are quite similar to those obtained with sintered powders used for luminous pigments. The crystalline structure of long persistent $SrAl_2O_4:Eu^{2+},\;Dy^{3+}$ phosphor single crystal was determined by X-ray diffraction.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.4
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• pp.532-542
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• 1996

The electrical and optical properties of the annealed $LiNbO_{3}$ single crystal with congruently melting composition and MgO or ZnO doped $LiNbO_{3}$ single crystal grown by the FZ method. The electrical and optical properties such as electrical conductivity, dielectric constant (Curie temperature), electro-mechanical coupling factor, optical transmittance and refractive indices of the grown crystals were measured and the nonlinear refractive indices of the grown crystals were calculated theoretically. The doping effects of MgO and ZnO were investigated by comparing the electrical and optical properties of the undoped $LiNbO_{3}$ single crystal and those of the $LiNbO_{3}$ single crystals doped with MgO or ZnO.

• Korean Journal of Crystallography
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• v.11 no.1
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• pp.16-21
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• 2000

(Yb/sub x/Y/sub 1-x/)Ca₄O(BO₃)₃ single crystals where x=0.3,8,15,20% were grown by Czochralski Method. The crystals grown under the optimum conditions were transparent and colorless with good crystal form. Using polarizing microscope, crystal defects such as parasite crystals and bubbles were detected depending on the composition of melts and pulling rates. The optimum growth parameters for high quality of single crystals were 15∼20 rpm of rotation rate and 2mm/h of pulling rate at the flow rate of 2 l/min of Nitrogen gas. The relationship between crystal axes and optical axes was investigated by optical crystallographic method, polarization technique and single crystal X-ray method. From the spectroscopic measurements, it was confirmed that there were strong absorption bands at 900 and 976.4 nm and strong emission band at 976.4 nm in Yb/sup 3+/ ion doped YCa₄O(BO₃)₃ crystal. For the application of second harmonic generation of 1.064 ㎛ laser, non-linear optical devices with θ=32.32° and Ψ=0°, λ/10 of flatness and the size of 6x8x5.73 mm were fabricated from the grown YCa₄O(BO₃)₃ crystal.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.7 no.4
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• pp.548-554
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• 1997

The single crystal of $Mg_{0.16}Zn_{0.84}$Te:Co(Co:0.01 mole%) was grown by vertical Bridgman method. The crystal structure of $Mg_{0.16}Zn$_{0.84}$Te:Co and optical absorption properties of this compound were studied. The grown single crystal has a cubic structure and a lattice constant a=6.1422 $\AA$ were determined by X-ray diffraction. As a result of the optical absorption spectra of $Mg_{0.16}Zn_{0.84}$Te:Co, the intracenter transitions due to $Co^{2+}$ ions were detected for $A-band:^4A_2(^4F){\to}^4T_2(^4F),\; B-band:^4A_2(^4F){\to}^4T_1(^4F), C- band:^4A_2(^4F){\to}^4T_1(^4P)$.The charge transfer transition near the absorption edge was observed in the wavelength range of 550 to 770 nm. According to the crystal field theory, the crystal field parameter(Dq) and the Racah parameter(B) were determined.