• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 추계학술대회 초록집
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• pp.49.1-49.1
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• 2010

본 연구에서는 증착법에 의해 제조된 다결정 실리콘을 이용한 태양전지 제작과 관련하여 다결정 실리콘 씨앗층 제조를 위한 기판에 대하여 연구를 수행하였다. 다결정 실리콘 씨앗층을 제조할 수 있는 기술중 aluminum-induced layer exchange(ALILE) 공정을 이용하여 다결정 실리콘 씨앗층을 제조하였다. glass/Al/oxide/a-Si 구조로 알루미늄과 비정질 실리콘 계면에 알루미늄 산화막을 다양한 두께로 형성시켜, 알루미늄 유도 결정화에서 산화막의 두께가 결정화 특성에 미치는 영향, 결정결함, 결정크기에 대하여 연구하였다. 형성된 다결정 실리콘 씨앗층 막의 특성은 OM, SEM, FIB, EDS, Raman spectroscopy, XRD, EBSD 을 이용하여 분석하였다. 그 결과 산화막의 두께가 증가할수록 결함도 함께 증가하였다. 16nm 두께의 산화막 구조에서 <111> 방향의 우선배향성을 가진, $10{\mu}m$의 sub-grain 결정립을 갖는 씨앗층을 제조 하였다.

• 한국세라믹학회지
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• 제37권6호
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• pp.530-536
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• 2000

During the grain growth of the PZT thin films by selective nucleation method using PZT seed, it was found that the grain size was saturated with the annealing temperature. The saturation of grain size was analyzed by the interfacial energy which appeared during the crystallization. The factors affecting the saturation of grain size were found to be the interfacial energy between perovskite phase and pyrochlore phase, and PZT thin film and the bottom Pt electrode. When the ion damage was introduced to the grain-size saturated PZT thin films, further lateral growth was observed. Pt bottom electrode thickness was changed to control the interfacial energy between the PZT thin film and the Pt bottom electrode. When Pt thickness was increased, the grain size was also increased, because the lattice parameter of Pt films was increased with the thickness of the Pt films. The incubation time of nucleation was increased with the amount of the ion damage on the Pt films.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.429-429
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• 2010

TFT 제조 방법 중 LTPS (Low Temperature Polycrystalline Silicon)는 저온과 저비용 등의 이점으로 인하여 flat panel display 제작에 널리 사용된다. 이동도와 전류 점멸비 등에서 이점을 가지는 ELA(Excimer Laser Annealing)가 널리 사용되고 있지만, 이 방법은 uniformity 등의 문제점을 가지고 있다. 이를 극복하기 위한 방법으로 MICC(Metal Induced Capping Crystallization)이 사용되고 있다. 이 방법은 $SiN_x$, $SiO_2$, SiON등의 capping layer를 diffusion barrier로 위치시키고, Ni 등의 금속을 capping layer에 도핑 한 뒤, 다시 한번 열처리를 통하여 a-Si에 Ni을 확산시키킨다. a-Si 층에 도달한 Ni들이 seed로 작용하여 Grain size가 매우 큰 film을 제작할 수 있다. 채널의 grain size가 클 경우 grain boundary에 의한 캐리어 scattering을 줄일 수 있기 때문에 MIC 방법을 사용하였음에도 ELA에 버금가는 소자의 성능과 안정성을 얻을 수있었다. 본 연구에서는 large grain TFT의 Gate bias stress에 따른 소자의 안정성 측정 및 분석에 목표를 두었다.

• 멤브레인
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• 제26권5호
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• pp.381-390
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• 2016

본 연구에서는 고순도의 모데나이트(Mordenite) 입자를 합성하기 위하여 천연 제올라이트를 시드로 사용하여 시드의 농도 및 수열합성 시간에 따른 천연 제올라이트 시드가 합성에 미치는 영향을 고찰하였다. 그 결과 시드가 입자의 형성에 큰 영향을 끼치는 것을 확인할 수 있었고 시드를 3 g/100 g batch 주입하여 $140^{\circ}C$에서 72시간 동안 수열합성을 진행하였을 때 $1-2{\mu}m$ 사이즈의 고순도 모데나이트 입자를 합성할 수 있었다. 이를 통해 모데나이트 입자의 성장 기구를 규명할 수 있었으며, 모데나이트 입자 형성에 있어 시드는 첫째, 구형 모데나이트 전구체 형성 자리 공급의 역할과, 둘째 모데나이트 원료 물질 소스 역할을 한다는 것을 알 수 있었다. 합성된 모데나이트 입자의 가스 흡착량 분석 결과 $CO_2$ 기체의 흡착량이 97.19 mg/g로 다른 가스들에 비해 비교적 높은 흡착성능을 보였으며, $CO_2/H_2$의 선택도가 가장 우수한 것으로 나타났다. 따라서 이러한 결과들을 바탕으로 용도에 맞는 고순도 상의 모데나이트 입자를 합성할 수 있음을 확인하였고 보다 낮은 가격으로 우수한 분리성능을 갖는 분리막 소재개발에 활용할 수 있을 것이라 판단된다.

• 한국결정성장학회지
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• 제13권1호
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• pp.5-14
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• 2003

Principles of a novel pulse growing method are described. The method realized in the crystal growing on a seed from melts under raw melt feeding provided a more reliable control of the crystallization process when producing large alkali halide crystals. The slow natural convection of the melt in the crucible at a constant melt level is intensified by rotating the crucible, while the crystal rotation favors a more symmetrical distribution of thermal stresses over the crystal cross-section. Optimum rotation parameters for the crucible and crystal have been determined. The spatial position oi the solid/liquid phase interface relatively to the melt surface, heaters and the crucible elements are considered. Basing on that consideration, a novel criterion is stated, that is, the immersion extent of the crystallization front (CF) convex toward the melt. When the crystal grows at a <> CF immersion, the raised CF may tear off from the melt partially or completely due to its weight. This results in avoid formation in the crystal. Experimental data on the radial crystal growth speed are discussed. This speed defines the formation of a gas phase layer at the crystal surface. The layer thickness il a function of time a temperature at specific values of pressure in the furnace and the free melt surface dimensions in the gap between the crystal and crucible wall. Analytical expressions have been derived for the impurity component mass transfer at the steady-state growth stage describing two independent processes, the impurity mass transfer along the <> path and its transit along the <> one. The heater (and thus the melt) temperature variation is inherent in any control system. It has been shown that when random temperature changes occur causing its lowering at a rate exceeding $0.5^{\circ}C/min$, a kind of the CF decoration by foreign impurities or by gas bubbles takes place. Short-term temperature changes at one heater or both result in local (i.e., at the front) redistribution of the preset axial growth speed.

• Korean Chemical Engineering Research
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• 제51권1호
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• pp.151-156
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• 2013

Polydimethylsiloxane (PDMS) 기반의 미세유체 시스템을 이용해 탄산칼슘의 결정화 실험을 수행하였다. 탄산칼슘의 결정화를 위한 다양한 반응방법 중 액체-액체 반응을 위해 염화칼슘 수용액과 탄산나트륨 수용액을 사용하였고 아스파르트산을 첨가하여 탄산칼슘 결정 중 베터라이트와 칼사이트의 생성에 어떤 차이를 보이는지 조사하였다. 그리고 탄산칼슘의 결정화 진행상황에서 결정핵 생성에 유리한 염화칼슘과 탄산나트륨의 비율을 조사하였다. 이를 위해 크리스마스트리 모양의 미세유체 반응기를 사용하여 채널 내부에 염화칼슘과 탄산나트륨의 농도구배를 형성하도록 하였다. 미세유체 결정화기 내부를 광학현미경으로 촬영한 결과, 탄산나트륨과 염화칼슘의 농도비가 2:1일 때 결정핵이 생성됨을 확인하였고 핵 생성 이후의 결정 성장 과정을 촬영하여 결정형태의 변화를 관찰하였다. 아스파르트산의 첨가 시에 결정핵 생성과 성장을 저해하며 전체 결정형태 중 베터라이트의 비율이 높아짐을 보였다.

• 한국세라믹학회지
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• 제26권4호
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• pp.479-486
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• 1989

According to the phase diagram, 6Bi2O3.GeO2 composition melts congruently at 93$0^{\circ}C$ and forms a stable ${\gamma}$-6Bi2O3.GeO2 crystal phase below the melting point. But when the melt of this composition was cooled at a rate 1-15$0^{\circ}C$/min without tapping by a glass rod or impurity addition, a metastable $\delta$-6Bi2O3.GeO2 crystal phase was formed. It is due to that as the nucleation energy barrier of $\delta$-6Bi2O3.GeO2 crystals, which have more open and defective structure, is lower than that of ${\gamma}$-6Bi2O3.GeO2 crystals. When impurities or ${\gamma}$-6Bi2O3.GeO2 crystals existed in the melt, stable ${\gamma}$-6Bi2O3.GeO2 crystal phase was formed at various cooling rate. It is because of that the impurities or the ${\gamma}$-6Bi2O3.GeO2 crystals role as a seed crystal and as a result the nucleation energy barrier of ${\gamma}$-6Bi2O3.GeO2 crystals is lowered.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.366-367
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• 2006

Different orientated SBN thin films were deposited by Ion Beam Sputtering, and electric properties were measured on each orientation. Ferroelectric $Sr_xBa_{1-x}Nb_2O_6$(SBN) has excellent electro-optic, photo-refractive, piezoelectric, pyroelectric properties. SBN thin film has been deposited by various method, of sol-gel, PLD, CVD, sputtering, etc.. To avoid lead pollution of Pb-system perovskite ferroelectric materials. SBN thin films were fabricated for pyroelectric IR sensor. Using the ceramic target of the same composition and Pt(100)/$TiO_2/SiO-2$/Si(100) substrate, crystallization and orientation behavior as well as electric properties of the films were examined. Seed layer and thin films thickness was controlled to observe the effect on preferred orientation. We measured I-V, C-V, P-E hysteresis to characterize electric-properties on each orientations.

• 한국작물학회지
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• 제41권spc1호
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• pp.110-122
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• 1996

The n-3 family fatty acids containing ${\alpha}$-linolenic acid(18:3, ALA) have been known as physiological activation materials such as inhibitory effects on the incidence of hyper-tension, coronary heart disease and cancers as well as the control of senilc dementia. Although a lot of ALA(about $63\%$) are contained in perilla oil, it has not been commercialized yet because the purification technique of the ALA has not been well established. The procedure of purification of ALA from perilla oil was saponified with 1 N-KOH /ethanol and then saturated and low level unsaturated fatty acids were removed by low-temperature crystallization method. The concentrated unsaturated fatty acids (containing about $75\%$ ALA) went down through the silver nitrate-impregnated silica column chromatography for separation of high purity of ALA. The results obtained we Fraction B, C and D contained ALA more than $85.5\%$(recovery, >$88.9\%,\;95.4\%$(recovery, >$54.4\%$) and $99.9\%$(recovery, >$31.5\%$) in purity, respectively. Seed oil content of the tested varieties were ranged from 34.8 to $54.1\%$ with $45.3\%$ of varietal means. The major omega fatty acids contained in the oil were oleic acid(n-9) $15.2\%$, linoleic acid(n-6) $13.9\%$ and linolenic acid(n-3) $63.1\%$ in the mean value. Varietal variation of n-9, 6 and 3 fatty acids ranged of $9.5\~21.4\%,\;9.1\~20.4\%$ and $50.6\~70.5\%$ respectively. Unsaturated fatty acid were averaged $92.2\%$ of seed oil in fatty acid composition. The ratios of n-6 to n-3 ranged of $0.13\~0.34\%$($0.22\%$ in mean value). The highest n-3 fatty acid variety was Yecheonjong being $70.5\%$. The lowest variety in ratios of n-6 to n-3 was Goseongjong being $0.13\%$. Oil content showed positive correlation with stearic acid and linolenic acid, while the negative correlation with oil content and linoleic acid. On the other hand, A significant negative correlation were showed between linolnic acid and the ratios n-6/n-3 fatty acid, saturated fatty acid. Saturated fatty acid was highly correlated with unsaturated fatty acid negatively being $r= -0.723^{**}$.

• 한국막학회:학술대회논문집
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• 한국막학회 2004년도 Proceedings of the second conference of aseanian membrane society
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• pp.86-89
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• 2004

The present study reports the preparation of a compact ZSM-5 membrane showing high thermal stability and high separation factors, especially n-/i-butane isomers at high temperatures. ZSM-5 membrane was prepared on a porous $\alpha$-Al$_2$O$_3$ tube (an average pore diameter, ca. 100 nm) at 18$0^{\circ}C$ by the seed-assisted crystallization method. The XRD and SEM results showed that a thin zeolite layer (ca. 1 ${\mu}{\textrm}{m}$) was formed on the support surface. The single gas permeances of $N_2$, H$_2$, SF$_{6}$, n-butane, and i-butane were taken at 27$0^{\circ}C$. i-Butane permeance hardly changed after repeated thermal treatments up to 40$0^{\circ}C$, indicating the membrane is thermally stable. On the other hand, other single gas permeances increased when the membrane was further dried at 40$0^{\circ}C$, indicating thermal pretreatment at 27$0^{\circ}C$ could not remove all the adsorbed species in the membrane. i-Butane and SF$_{6}$ permeances were significantly lower than the permeances of smaller molecules, indicating that the membrane has a low concentration of defects. The ideal selectivities at 27$0^{\circ}C$ were 61 for $H_2$/i-butane and 47 for $H_2$/SF$_{6}$. The temperature dependency of n/i-butane ideal selectivities and separation factors for an equimolar n/i-butane mixture was studied. The ideal selectivity showed a maximum of 36 at 30$0^{\circ}C$. The separation factors increased with temperature and reached around 12 at 300-40$0^{\circ}C$, which were much higher than those reported in the literature.ature.