• 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.

• 한국결정성장학회:학술대회논문집
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• 한국결정성장학회 1996년도 The 9th KACG Technical Annual Meeting and the 3rd Korea-Japan EMGS (Electronic Materials Growth Symposium)
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• pp.88-138
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• 1996

Electronics grew up to the largest industry in the world supported by Si wafer. In near future, the Si wafer may use 300mm in diameter for economic requirement. This size wafer may use to produce large logic chip, 256Mbit DRAM, and other large complex and high density chip. Then, the quality including flatness and crustal characters may be required very high performance. And, their price should be reasonable and high quantity may be required. These requirements should be solve lot of hard problems of crystal growth, wafering mechanical processing and their cost problems. In this presentation, I may discuss following items.

• Current Photovoltaic Research
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• 제2권3호
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• pp.84-87
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• 2014

Protection of solar cell surface is important to prevent from dust, pollen, sand, etc. Therefore, development of large area antifouling film is urgent for high performance of solar cells. The surface of silica spheres was modified to fabricate large area antifouling film. The surface of monodisperse silica spheres has been modified with 3-(trimethoxysilyl) propylmethacrylate (TMSPM) to fabricate large area photonic crystal. Although the surface modification of silica spheres with TMSPM has been failed for the base catalyst, the second trial using acid catalyst showed the following results. The FTIR absorption peak at $1721cm^{-1}$ representing C=O stretching vibration indicates that the TMSPM was attached on the surface of silica spheres. The methanol solution comprised of the surface modified silica spheres (average diameter of 380 nm) and a photoinitiator was poured in the patterned silicon wafer with the dimension of 10 cm x 10 cm and irradiated UV-light during the self-assembly process. The result showed large area crack and defect free nanostructures.

• 열처리공학회지
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• 제33권1호
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• pp.20-24
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• 2020

Single crystal diamonds are in great demand in such fields as mechanical, electronic applications and optoelectronics. Large area single crystal diamonds are attracting attention in future industries for mass production and low cost. In this study, hot filament CVD (HFCVD) is used to grow large area single crystal diamond. However, the growth rate of large area single crystal diamond using HFCVD is known to be very low. The goal of this study is to use single crystal diamond substrates in HFCVD with methane-hydrogen gas mixtures to increase the growth rate of single crystal diamond and to optimize the conditions by analysing the effects of deposition conditions for high quality crystallinity. The deposition pressure, the ratio of CH₄/H₂ gas, the substrate temperature and the distance between the filament and the substrate were optimized. The sample used a 4×4 (mm²) size single crystal diamond substrate (100), the CH₄/H₂ gas ratio was fixed at 5%, the substrate temperature was synthesized to about 1000℃. At this time, the deposition pressure was changed to three types of 50, 75, 85 Torr and deposited. Finally, optimization was investigated under pressure conditions to analyse the growth rate and quality of single crystal diamond.

• 한국초전도ㆍ저온공학회논문지
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• 제24권3호
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• pp.35-40
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• 2022

To fabricate large grain YBCO bulk superconductors by melt process, Sm123 single crystal with a high melting point are mostly used as seeds. However, it also uses Y123 film deposited on MgO single crystal substrate. This study investigated the growth behavior of the Y123 grain during a melt process when single grain YBCO bulk was used as a seed. Single grain Y123 bulk was grown when the seed size was small. When the seed size was relatively large, multiple grains were grown but the grains were still large. Y123 seed crystal was completely decomposed during high temperature anneal at 1040℃ and new Y123 crystals were nucleated during a slow cooling stage below a peritectic temperature. Thereafter, newly formed Y123 crystals from the seed area are thought to grow into the Y1.8 powder compact. The crystallographic orientations of newly nucleated Y123 grains are independent of the crystallographic orientation of Y123 seed. It is thought that the crystallographic orientation of newly nucleated Y123 crystal can be controlled by using Y211-free Y123 single crystal as a seed of homo-seeding melt growth.

• 대한수학회지
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• 제51권2호
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• pp.427-442
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• 2014

A previous work gave a combinatorial description of the crystal B(${\infty}$), in terms of certain simple Young tableaux referred to as the marginally large tableaux, for finite dimensional simple Lie algebras. Using this result, we present an explicit description of the crystal B(${\lambda}$), in terms of the marginally large tableaux, for the $G_2$ Lie algebra type. We also provide a new description of B(${\lambda}$), in terms of Nakajima monomials, that is in natural correspondence with our tableau description.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.266.1-266.1
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• 2013

Large-scale single-crystal organic nanowire arrays were generated using a direct printing method (liquidbridge- mediated nanotransfer molding) that enables the simultaneous synthesis, alignment and patterning of nanowires from molecular ink solutions. Using this method, single-crystal organic nanowires can easily be synthesized by self-assembly and crystallization of organic molecules within the nanoscale channels of molds, and these nanowires can then be directly transferred to specific positions on substrates to generate nanowire arrays by a direct printing process. Repeated application of the direct printing process can be used to produce organic nanowire-integrated electronics with two- or three-dimensional complex structures on large-area flexible substrates. This efficient manufacturing method is used to fabricate all-organic nanowire field-effect transistors that are integrated into device arrays and inverters on flexible plastic substrates.

• 한국결정성장학회지
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• 제6권1호
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• pp.11-18
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• 1996

Czochralski법으로 성장된 대구경(8인치 이상) 규소 단결정속에 폰재하는 결정 결 함을 규명하였다. Ring형 산화 적충 결함(Oxidation Induced Stacking Faults, 일명 OISF)의 발생 형태를 조사하였다. Minority life time을 mappmg하여 본 결과, rmg형 OISF의 폰재는 재료의 전기적 성질에 영향을 미칠 가능성이 높은 것으로 확인되었다. OISF의 핵 생성에 미치는 냉각 속도의 영향을 조사한 결과 homogeneous적 핵 생성 및 성장 현상을 확인할 수 있었다. 또한 COP(Crystal Originated Particle)의 주원인인 FPD(Flow Pattern Defects)의 발생은 용 체의 응고 속도에 크게 화우됨을 발견하였다. 이들 결함의 상반된 발생 현상의 제어를 위하여 는 인상 속도는 느리게, 또한 $950^{\circ}C$ 근처에서의 냉각속도는 빠르게 하는 것이 바람직한 것으로 결함 발생 제어 모델이 제시되었다.

• Current Optics and Photonics
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• 제3권4호
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• pp.298-303
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• 2019

We propose a photonic quasi-crystal fiber (PQF) for supporting up to 14 orbital angular momentum (OAM) modes with low and ultra-flat dispersion characteristics over the C+L bands. The designed PQF which consists of a large hollow center and quasi structural small air holes in the clad region exhibits low confinement losses and a large effective index separation (>$10^{-4}$) between the vector modes. This proposed fiber could potentially be exploited for mode division multiplexing and other OAM mode applications in fibers.

• 한국결정성장학회지
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• 제4권1호
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• pp.76-82
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• 1994

고온용액법(high temperature solution grwth)에 의해 $K_6P_4O_13$의 flux로 부터 KTP 단결정을 성장시켰다. Inclusion이 없는 KTP 단결정을 성장시키기 위해 성방로내 온도기울기, 결정의 회전, 종자결정의 방위, 냉각속도를 조절하였다. 성장된 KTP 단결정은 inclusion이 없었으며, 크기는 $10(a){\times}28(b){\times}33(c)mm^3$ 이었다. 또한 KTP 단결정 boule의 위치에 따른 SHG 출력 특성 측정 및 TEM 분석에 의해 종자결정 주위의 광학적 불균일성의 원인을 조사하였다.