• 한국진공학회:학술대회논문집
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• 한국진공학회 1996년도 제11회 학술발표회 논문개요집
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• pp.40-41
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• 1996

Nitridation technique has been receiving much attention for the formation of a thin nitrided buffer layer on which high quality nitride films can be formedl. Particularly, gallium nitride (GaN) has been considered as a promising material for blue-and ultraviolet-emitting devices. It can also be used for in situ formed and stable passivation layers for selective growth of $GaAs_2$. In this work, formation of a thin nitrided layer is investigated. Nitrogen electron cyclotron resonance(ECR)-plasma is employed for the formation of thin nitrided layer. The plasma source used in this work is a compact ECR plasma gun3 which is specifically designed to enhance control, and to provide in-situ monitoring of plasma parameters during plasma-assisted processing. Microwave power of 100-200 W was used to excite the plasma which was emitted from an orifice of 25 rnm in diameter. The substrate were positioned 15 em away from the orifice of plasma source. Prior to nitridation is performed, the surface of n-type (001)GaAs was exposed to hydrogen plasma for 20 min at $300{\;}^{\circ}C$ in order to eliminate a native oxide formed on GaAs surface. Change from ring to streak in RHEED pattern can be obtained through the irradiation of hydrogen plasma, indicating a clean surface. Nitridation was carried out for 5-40 min at $RT-600{\;}^{\circ}C$ in a ECR plasma-assisted molecular beam epitaxy system. Typical chamber pressure was $7.5{\times}lO^{-4}$ Torr during the nitridations at $N_2$ flow rate of 10 seem.(omitted)mitted)

• 전자공학회논문지D
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• 제36D권1호
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• pp.57-62
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• 1999

유리기판 위에 다결정 실리콘 박막 트랜지스터(Thin Film Transistor, TFT)를 형성하기 위해서 램프 Scanning 열처리 장치를 개발하였다. 선형 램프를 Scanning 함으로써 대면적 유리기판에의 적용 가능성을 높였으며 TFT의 채널 부분은 금속 유도 측면 결정화 방법에 의해 결정화 시켰다. 할로겐 램프에 의한 빛은 투명 유리기판은 가열시키지 않고 ,island 행태의 실리콘 박막만을 가열시킬 수 있었다. 실리콘 산화막으로 이루어진 Capping layer를 적용하였고 이때의 성장 속도는 Capping layer가 없는 경우보다 35배 정도로 빠른 MILC 성장 속도를 나타내었다. 할로겐 램프를 약 1.4mm/sec의 속도록 Scanning한 경우 유리기판의 손상 없이 18-27${\mu}m/scan$ 정도의 결정화를 나타내었다. 이와 같이 제작된 다결정 실리콘 박막으로 제작된 TFT는 전자이동도 130$cm^2/V{\cdot}sec$의 우수한 특성을 나타내었다.

• 한국산림과학회지
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• 제65권1호
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• pp.60-67
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• 1984

한국산(韓國産) 단풍나무속(屬) 6개(個) 수종(樹種)의 심재내(心材內) 지질(脂質)을 추출(抽出)하여 Thin Layer Chromatography에 의한 방법(方法)으로 종(種)을 식별(識別)하였으며, 정색반응(呈色反應)의 특징(特徵)으로 유연관계(類緣關係)를 조사(調査)한 결과(結果)를 요약(要約)하연 다음과 같다. 1) 6개(個) 수종(樹種) 심재(心材)의 지질함량(脂質含量)은 유리암질(遊離暗質)이 평균(平均) 2.85%, 결합지질(結合脂質)이 1.54%이었으며, 전지질(全脂質)은 4.39%이었다. 2) TLC 정색반응(呈色反應) 특징(特徵)에 의해서 단풍나무속(屬) 6개(個) 수종(樹種) ; 신나무, 고로쇠나무, 네군도단풍, 단풍나무, 은단풍, 복자기를 식별(識別)할 수 있었으며, 정색반응(呈色反應)에 의한 유연관계(類緣關係)를 보면 단풍나무와 복자기가 근연(近緣)임을 알 수 있었다.

• 공업화학
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• 제1권2호
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• pp.249-255
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• 1990

Thin layer chromatography를 사용하여 음이온성 및 비이온성 계면활성제의 신속한 분리 및 정성분석에 필요한 용매조건들을 조사하였다. 알킬사슬의 종류와 alkylene oxide의 분포에 따른 분리특성을 이용하여 polyoxyalkylene 계 비이온성 계면활성제들을 간단히 정성 분석 할 수 있었으며, densitometer를 사용하여 polyoxyethylenated nonyl phenol의 ethylene oxide(EO)에 따른 분포를 쉽게 비교할 수 있었다. 일련의 음이온성 계면활성제들을 $R_f$ 값과 발색되는 색으로 정성분석하였으며, 음이온성 및 비이온성 계면활성제 혼합물을 각각 분리하였다. 지방산계 계면활성제를 diester, monoester 및 미반응된 polyethylene glycol의 세 부분으로 농축 분리하여 그 혼합비율을 구하였다. 이상의 모든 실험은 전개용매를 80mm정도 전개시킨 상태에서 이루어졌고 분리에 걸린 시간은 13-20분 정도였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.479-479
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• 2011

Flexible inverters based on complementary thin-film transistor (CTFTs) are important because they have low power consumption and other advantages over single type TFT inverters. In addition, integrated CTFTs in flexible electronic circuits on low-cost, large area and mechanically flexible substrates have potentials in various applications such as radio-frequency identification tags (RFIDs), sensors, and backplanes for flexible displays. In this work, we introduce flexible complementary inverters using pentacene and amorphous indium gallium zinc oxide (IGZO) for the p-channel and n-channel, respectively. The CTFTs were fabricated on polyimide (PI) substrate. Firstly, a thin poly-4-vinyl phenol (PVP) layer was spin coated on PI substrate to make a smooth surface with rms surface roughness of 0.3 nm, which was required to grow high quality IGZO layers. Then, Ni gate electrode was deposited on the PVP layer by e-beam evaporator. 400-nm-thick PVP and 20-nm-thick ALD Al2O3 dielectric was deposited in sequence as a double gate dielectric layer for high flexibility and low leakage current. Then, IGZO and pentacene semiconductor layers were deposited by rf sputter and thermal evaporator, respectively, using shadow masks. Finally, Al and Au source/drain electrodes of 70 nm were respectively deposited on each semiconductor layer using shadow masks by thermal evaporator. Basic electrical characteristics of individual transistors and the whole CTFTs were measured by a semiconductor parameter analyzer (HP4145B, Agilent Technologies) at room temperature in the dark. Performance of those devices then was measured under static and dynamic mechanical deformation. Effects of cyclic bending were also examined. The voltage transfer characteristics (Vout- Vin) and voltage gain (-dVout/dVin) of flexible inverter circuit were analyzed and the effects of mechanical bending will be discussed in detail.

• Journal of Biosystems Engineering
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• 제42권3호
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• pp.190-198
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• 2017

Purpose: A thin-layer drying equation was developed to analyze the drying processes of soybeans (white and black beans) and investigate drying conditions by verifying the suitability of existing grain drying equations. Methods: The drying rates of domestic soybeans were measured in a drying experiment using air at a constant temperature and humidity. The drying rate of soybeans was measured at two temperatures, 50 and $60^{\circ}C$, and three relative humidities, 30, 40 and 50%. Experimental constants were determined for the selected thin layer drying models (Lewis, Page, Thompson, and moisture diffusion models), which are widely used for predicting the moisture contents of grains, and the suitability of these models was compared. The suitability of each of the four drying equations was verified using their predicted values for white beans as well as the determination coefficient ($R^2$) and the root mean square error (RMSE) of the experiment results. Results: It was found that the Thompson model was the most suitable for white beans with a $R^2$ of 0.97 or greater and RMSE of 0.0508 or less. The Thompson model was also found to be the most suitable for black beans, with a $R^2$ of 0.97 or greater and an RMSE of 0.0308 or less. Conclusions: The Thompson model was the most appropriate prediction drying model for white and black beans. Empirical constants for the Thompson model were developed in accordance with the conditions of drying temperature and relative humidity.

• 한국전기전자재료학회논문지
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• 제24권5호
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• pp.392-397
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• 2011

The effect of various post-annealing temperature to sputtered Pb(Zr,Ti)$O_3$ (PZT) thin films was investigated. The crystallization process, surface morphology and the electrical characteristics strongly depends on the rapid thermal annealing (RTA). In radio frequency (RF) sputtering methods, there were many papers mostly forcing on the crystal forming and the surface variations with different elements distribution (Pb, Ti, Zr, O) on the surface of the PZT layer. In this experiment, the post-annealing treatment promoted the Pb volatilization in PZT thin film and affected the Ti diffused throughout the Pt layer into the PZT layer. Second ion mass spectroscopy (SIMS) analysis was employed to show that the Pb element in the PZT layer was decreased at the same time the Ti element mass was slight decreased than Pb with increasing RTA temperature. That result prove the content of Pb affect the PZT thin film property.

• 생명과학회지
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• 제23권4호
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• pp.537-541
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• 2013

Biodiesel 중의 glycerol을 분석하기 위하여 TLC를 이용하여 몇 가지 보고된 이동상에서 glycerol을 분석하였다. 그 중에서 acetonitrile : distilled water (85:15, v/v)를 이동상으로 하여 TLC를 수행하였을 경우에 짧은 시간에 명확한 glycerol band를 확인할 수 있었다. X축의 glycerol 농도를 log scale로 하고, TLC의 glycerol 이미지 면적을 Y축으로 하여 3.0-0.0625 (%, w/v)의 glycerol 농도범위에서 표준곡선을 작성할 수 있었으며, 이를 이용하여 0.2 (%, w/v)의 glycerol을 포함하는 biodiesel 시료에서 유의성 있게 glycerol을 정량분석 할 수 있음을 확인하였다. 이러한 결과는 chemical assay, enzymatic assay를 이용한 glycerol 분석과 비교하여 매우 유사한 결과이며, TLC를 이용한 biodiesel 중의 glycerol 정량법은 특별한 분석기기를 사용할지 않아도 되는 편리하고 간편한 방법으로 생각되어진다.

• 한국진공학회지
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• 제19권2호
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• pp.91-95
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• 2010

상온에서 고품질의 $TiO_2$ 박막을 제조하기 위하여 titanium isopropoxide [Ti(OCH$(CH_3)_2)_4$, TIP]와 $H_2O$을 이용한 자외선 활성화 원자층 증착(UV-enhanced atomic layer deposition: UV-ALD) 기술을 개발하였다. UV-ALD 기술은 상온에서 자체제어 표면 반응(self-limitting surface reaction)을 통해 균일하고 고품위 등방 특성을 갖는 순수한 $TiO_2$ 박막 증착이 가능하였다. ALD 반응 시 조사되는 자외선은 Si 기질 위에 우수한 접착력을 가지는 고품질의 $TiO_2$ 박막을 얻는데 효과적이었다. UV-ALD 기술은 높은 단차비(aspect ratio)를 가지는 trench 기질 위에 균일한 $TiO_2$ 박막을 증착하는 데에 적용되었다.

• 한국재료학회지
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• 제30권10호
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• pp.566-572
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• 2020

In the recent years, thin film solar cells (TFSCs) have emerged as a viable replacement for crystalline silicon solar cells and offer a variety of choices, particularly in terms of synthesis processes and substrates (rigid or flexible, metal or insulator). Among the thin-film absorber materials, SnS has great potential for the manufacturing of low-cost TFSCs due to its suitable optical and electrical properties, non-toxic nature, and earth abundancy. However, the efficiency of SnS-based solar cells is found to be in the range of 1 ~ 4 % and remains far below those of CdTe-, CIGS-, and CZTSSe-based TFSCs. Aside from the improvement in the physical properties of absorber layer, enormous efforts have been focused on the development of suitable buffer layer for SnS-based solar cells. Herein, we investigate the device performance of SnS-based TFSCs by introducing double buffer layers, in which CdS is applied as first buffer layer and ZnMgO films is employed as second buffer layer. The effect of the composition ratio (Mg/(Mg+Zn)) of RF sputtered ZnMgO films on the device performance is studied. The structural and optical properties of ZnMgO films with various Mg/(Mg+Zn) ratios are also analyzed systemically. The fabricated SnS-based TFSCs with device structure of SLG/Mo/SnS/CdS/ZnMgO/AZO/Al exhibit a highest cell efficiency of 1.84 % along with open-circuit voltage of 0.302 V, short-circuit current density of 13.55 mA cm^-2, and fill factor of 0.45 with an optimum Mg/(Mg + Zn) ratio of 0.02.