• 한국결정성장학회지
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• 제18권1호
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• pp.1-4
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• 2008

The growth of composite-structured Nd:$GdVO_4$ single crystal rods by the double die EFG method is reported. Two crucibles are combined with an outer and inner die for ascending of different melt. The composite-structured Nd:$GdVO_4$ single crystal rods with a length of 50 mm and an outer diameter of 5 mm including of inner Nd-doped core region with diameter 3 mm were grown successfully. Nd distribution in the, radial direction has graded profile from result of EPMA. Absorption coefficient in the core region at 808 nm was $42cm^{-1}$. Finally, we demonstrated the laser oscillation using our composite crystal and 2-W output was obtained.

• 한국결정성장학회지
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• 제28권4호
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• pp.148-151
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• 2018

물리기상이동법(Physical Vapor Transport(PVT) method)을 적용하여 질화알루미늄 단결정을 성장하였다. 자체적으로 성장하고 제조한 직경 33 mm 크기의 종자결정을 사용하여 직경 46 mm, 길이 7.6 mm 크기의 벌크단결정을 성장하였으며, 성장 온도는 $1950{\sim}2100^{\circ}C$, 성장 압력은 0.1~1 atm의 범위에서 조절하여 반복 성장을 통하여 성장한 결과를 보고하고자 한다.

• 한국결정성장학회지
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• 제7권1호
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• pp.76-80
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• 1997

직경 55 mm의 ZnSe 단결정을 수소분위기에서 seeded chemical vapor transport법에 의해 성장하였고, 성장 parameter들이 결정 결함에 미치는 영향을 조사하였다. Chemical etching에 의한 EPD 측정, X-ray rocking curve 측정, photolumlnescence 측정으로 성장된 단결정의 특성을 평가하였다.

• 한국결정성장학회지
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• 제26권4호
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• pp.135-138
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• 2016

AlN 결정을 PVT(물리 기상 이동법, Physical Vapor Transport) 법으로 성장함에 있어 결정립의 성장 거동을 관찰하였다. 작은 AlN 결정립이 성장한 이후 결정립들은 이웃한 결정립과 합쳐지면서 성장하는 거동을 보였다. 이를 실체현미경을 이용하여 관찰한 결과를 보고하고자 한다.

• 한국결정성장학회지
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• 제11권6호
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• pp.274-284
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• 2001

A stoichimetric mixture of evaporating materials for $AgInS_2$ single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films. $AgInS_2$mixed crystal was deposited on thorughly etched semi-insulating GaAs(100) substrate by the Hot wall Epitaxy (HWE) system. The source and substrate temperatures were $680^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of the single thin films was investigated by the photoluminescence and double crystal X-ray diffraction(DCXD). The carrier density and mobility of $AgInS_2$ single crystal the films measured from Hall effect by van der Pauw method are $9.35\times 10^{16}/\terxtm{cm}^3$ and $294\terxtm{cm}^2$/V.s at 293 K, respectively. From the optical absorption measurement the temperature dependence of the energy band gap on AgInS$_2$ single crystal thin film was found to be $E_g$(T)= 2.1365eV-($9.89\times 10^{-3}eV/T^2$/(2930+T). After the as-grown $AgInS_2$ single crystal thin films was annealed in $Ag^-S^-$ and In-atmospheres, the origin of point defects of AgInS$_2$ single crystal the films has been investigated by using the photoluminescence(PL) at 10K. The native defects of $V_{Ag},V_s, Ag_{int}$ and $S_{int}$ int/ obtained from PL measurements were classified as a donors or acceptors type. And we concluded that the heat-treatment in the S-atmosphere converted $AgInS_2$ single crystal thin films to an optical p-type. Also, we confirmed that In in $AgInS_2$ /GaAs did not form the native defects because In is $AgInS_2$ single crystal thin films did exist in the form of stable bonds.

• 한국결정성장학회지
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• 제27권1호
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• pp.57-63
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• 2017

High-purity ${\beta}-SiC$ powders for SiC single-crystal growth were synthesized by direct carbonization. The use of high-purity raw materials to improve the quality of a SiC single crystal is important. To grow SiC single crystals by the PVT method, both the particle size and the packing density of the SiC powder are crucial factors that determine the sublimation rate. In this study, we tried to produce high-purity ${\beta}-SiC$ powder with large particle sizes and containing low silicon by introducing a milling step during the direct carbonization process. Controlled heating improved the purity of the ${\beta}-SiC$ powders to more than 99 % and increased the particle size to as much as ${\sim}100{\mu}m$. The ${\beta}-SiC$ powders were characterized by SEM, XRD, PSA, and chemical analysis to assess their purity. Then, we conducted single-crystal growth experiments, and the grown 4H-SiC crystals showed high structural perfection with a FWHM of about 25-48 arcsec.

• 한국세라믹학회지
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• 제27권8호
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• pp.1050-1054
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• 1990

Rutile(TiO2) single crystals were grown by FZ method. Feed rod was sintered in the longitudinal tube-shaped furnace at 135$0^{\circ}C$ and optimum growth condition was growth rate 5-8mm/hr, rotation rate 30-40rpm. When crystal was growing, atomosphere was oxidized condition, and grown single crystal was annealed at 110$0^{\circ}C$. The rutile single crystals were oriented to [001] direction and color change of single crystals were related to atmosphere, and difference of electric conductivity and resistance was due to the fact above.

• 한국결정성장학회지
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• 제27권2호
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• pp.65-69
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• 2017

AlN 단결정을 $1600{\sim}1800^{\circ}C$의 온도에서 100 torr 이하의 진공하에서 $100^{\circ}C$ 간격으로 열처리하였다. AlN 단결정은 고주파유도가열 방식으로 가열되는 성장부를 갖는 성장장치를 사용하여 PVT법으로 얻어내었다. 단결정 시편들의 표면을 광학현미경으로 관찰하였으며, 성장된 압력 하에서 온도에 따라 형상이 달라짐을 알 수 있었다. 본 연구에서는 광학현미경 관찰 결과를 보고하고자 하며, 열처리 온도가 증가함에 따라 표면의 열에칭이 나타났는데, 이는 작은 에치핏의 형성을 통하여 관찰하였다.

• 한국결정성장학회지
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• 제15권6호
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• pp.222-224
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• 2005

In suite of their superior optical and laser properties rare-earth orthovanadate single crystals have not been adopted yet into extensive industrial applications because of crystal growth difficulties. The edge-defined film-fed-growth (EFG) technique was applied successfully for the production of such crystals. At first time 1 inch $LuVO_4$ single crystals were grown by the EFG technique using newly developed die construction of high porous iridium with the application of automatic diameter control system.

• 한국결정성장학회지
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• 제4권2호
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• pp.111-118
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• 1994

Crystal growth chamber 상부에 있는 reservoir에서 polycrystalline silicon powder를 연속적으로 feeding하면서 도가니 하부에 용융대를 형성시키고 seed를 meed를 dipping하여 회전시키면서 하부로 끌어내려 단결정을 성장시키는 연속성장법의 기본 원리를 확립하였고, 직접 고안 설계 제작한 연속성장 장치로 silicon 단결정을 성장시켰다. 본 연속성장법은 melt에 미치는 중력, 진동, melt의 표면장력, melt와 solid의 계면 장력, seed의 회전에 따른 원심력 등의 힘들이서로 상쇄되고 power, feeding양과 성장속도가 비례하여 적당한 조합을 이룰 때 안정한 연속성장을 할 수있다.