• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.497-497
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• 2012

산업의 발전함에 따라 고기능성 박막의 수요가 증가하고 있으며, magnetron sputtering, e-beam evaporation, ion beam 등을 이용한 박막 증착에 대한 연구가 많이 진행되고 있다. 그러나 기존 방법만으로는 박막 접착계면의 불균일로 인해 고기능성 박막 성장이 어렵다는 단점을 가지고 있다. 이러한 문제를 해결하기 위하여 박막 공정 중 고밀도 플라즈마 소스(high density plasma source)를 통해 추가적인 에너지를 인가하여 박막의 밀도를 bulk 수준으로 증가시키고 내부 응력을 조절하는 연구에 대한 관심이 커지고 있다. 특히 grid를 이용하여 플라즈마 내 이온의 입사에너지를 증가시킴으로써, 기존 공정보다 고기능성 박막을 구현할 수 있다. 본 연구에서는 RF power를 이용한 inductively coupled plasma를 통해 플라즈마를 생성시킨 후 grid에 DC power를 인가하는 플라즈마 소스를 개발하였으며, 시뮬레이션을 통해 plasma density와 ion current density, ion energy 분석 및 grid 디자인을 하였다. 개발된 플라즈마 소스는 ion energy analyzer를 통해 RF power 및 grid에 인가하는 power의 세기에 따라 이온화 정도 및 이온의 입사에너지를 측정하였다.

• 한국재료학회지
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• 제15권6호
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• pp.382-387
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• 2005

Polyvinylidene fluoride (PVDF) surface was irradiated and became superhydrophilic by low energy (180 eV) and high flux $(\~10^{15}/cm{\cdot}s)$ ion beam. As an ion source, a closed electron Hall drift thruster of $\phi=70mm$ outer channel size without grid was adopted. Ar, $O_2$ and $N_2O$ were used for source gases. When $N_2O^+$ and $O_2^+$ reactive gas ion beam were irradiated with the ion fluence of $5\times10^{15}/cm^2$, the wetting angle for deionized water was drastically dropped from $61^{\circ}\;to\;4^{\circ}\;and\;2^{\circ}$, respectively. Surface energy was also increased up to from 44 mN/m to 81 mN/m. Change of chemical component in PVDF surface was analyzed by x-ray photoelectron spectroscopy. Such a great increase of the surface energy was intimately related with the increase of hydrophilic group component in reactive ion irradiated PVDF surfaces. By using an atomic force microscopy, the root-mean-square of surface roughness of ion irradiated PVDF was not much altered compared to that of pristine PVDF.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1996년도 제10회 학술발표회 논문개요집
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• pp.102-102
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• 1996

This paper represents a new type low power High Frequency technological ion source (HF TIS) for ion - beam processing: the surface modification of materials, cleaning of surface, sputtering, coating of thin films, and polishing. The operational principle of HF TIS is based on the excitation of electrostatic waves in plasma located in the external magnetic field. Low power HF TIS with diameter 92 rom gives the opportunity to obtain beams of inert and chemically reactive gases with currents range from 5 to 150 mA (current density $0.015\;~\;3.5\;mA/\textrm{m}^2$) and ion beam energy 100 ~ 2500 eV at a HF power level 10 ~ 150 W. Three grid concave type ion optical system (IOS) is used for extraction and formation ofion beam.n beam.

• The Korean Journal of Ceramics
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• 제6권2호
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• pp.129-133
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• 2000

Boron nitride films were synthesized with $N_2$ion flux of low energy, up to 100 eV, at different substrate temperatures of no heating, 200, 400, 500, and $800^{\circ}C$, respectively. Boron was supplied by e-beam evaporation at the rate of $1.5\AA$/sec. For all the conditions, hexagonal BN (h-BN) phase was mainly synthesized and high resolution transmission electron microscopy (HRTEM) showed that (002) planes of h-BN phase were aligned vertical to the Si substrate. The maximum alignment occurred around $400^{\circ}C$. In addition to major h-BN phase, transmission electron diffraction (TED) rings identified the formation of cubic BN (c-BN) phase. But HRTEM showed no distinct and continuous c-BN layer. These results suggest that c-BN phase may form in a scattered form even when h-BN phase is mainly synthesized under small momentum transfer by bombarding ions, which are not reconciled with the macro compressive stress model for the c-BN formation.

• KIEAE Journal
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• 제16권1호
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• pp.57-65
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• 2016

Purpose: The purpose of this study is to analyze the energy performance by applying new technologies for passive and active control. Method: We selected new technologies for passive and active control which are based on formal study by analyzing technology applied to the High-Performance Buildings in various countries. Also, we analyzed energy saving potential for each technologies by breakdown the result of the energy saving rates in detail. Result: For the wall and roof insulating methods, preceding studies showed that up to 21% energy could be saved by improving roof insulation and applying proper outside insulation compared to non-insulation. For the windows and glazing system, preceding studies showed that Low-E glazing system could save up to 11% energy compared to single glazing system. Studies about solar and daylighting controls revealed that effective daylighting dimming control could save 13% of energy compared to uncontrolled situation. Studies on DOAS (Dedicated Outdoor Air System) showed that about 23% energy could be saved compared to standard VAV system. Studies on the active chilled beam showed that about 25% energy could be saved compared to standard VAV system and studies of applying UFAD (Under Floor Air Distribution) could consume 31% less energy than applying overhead system.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 하계학술대회 논문집 Vol.8
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• pp.414-414
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• 2007

In this study, Liquid Crystal (LC) alignment and tilt angle generation in Nematic Liquid Crystal (NLC) with negative dielectric anisotropy on the homeotropic PI surface with new ion beam exposure are reported. Also. high density of ion beam energy (DuoPIGatron type Ar ion gun) is used in this study. The tilt angle of NLC on the homeotropic Polyimide (PI) surface for all incident angles is measured about 38 degree and this has a stabilization trend. And the good LC alignment of NLC on the PI surface with ion beam exposure of $45^{\circ}$ incident angle was observed. Also the tilt angle of NLC on the homeotropic PI surface with ion beam exposure of $45^{\circ}$ had a tendency to decrease as ion beam energy density increase. The tilt angle could be controlled from verticality to horizontality. Also, the LC aligning capabilities of NLC on the homeotropic PI surface according to ion beam energy has the goodness in case of more than 1500 eV. Finally. the superior LC alignment thermal stability on the homeotropic PI surface with ion beam exposure can be achieved. For OCB(Optically Compensated Bend) mode driving, we can need pretilt angles control for fast response time. In this study, We success pretilt angles control. Consequently, this result can be applied for OCB mode.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.95.1-95.1
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• 2010

Transparent conducting ZnO films were deposited to apply DSSC Substrate on glass substrates at $500^{\circ}C$ by ionbeam-assisted deposition. Crystallinity, microstructure, surface roughness, chemical composition, electrical and optical properties of the films were investigated as a function of deposition parameters such as ion energy, and substrate temperature. The microstructure of the polycrystalline ZnO films on the glass substrate were closely related to the oxygen ion energy, arrival ratio of oxygen to Zinc Ion bombarded on the growing surface. The main effect of energetic ion bombardment on the growing surface of the film may be divided into two categories; 1) the enhancement of adatom mobility at low energetic ion bombardment and 2) the surface damage by radiation damage at high energetic ion bombardment. The domain structure was obtained in the films deposited at 300 eV. With increasing the ion energy to 600 eV, the domain structure was changed into the grain structure. In case of the low energy ion bombardment of 300 eV, the microstructure of the film was changed from the grain structure to the domain structure with increasing arrival ratio. At the high energy ion bombardment of 600 eV, however, the only grain structure was observed. The electrical properties of the deposited films were significantly related to the change of microstructure. The films with the domain structure had larger carrier concentration and mobility than those with the grain structure, because the grain boundary scattering was reduced in the large size domains compared with the small size grains. The optical transmittance of ZnO films was dependent on a surface roughness. The ZnO films with small surface roughness, represented high transmittance in the visible range because of a decreased light surface scattering. By varying the ion energy and arrival ratio, the resistivity and optical transmittance of the films were varied from $1.1{\times}10^{-4}$ to $2.3{\times}10^{-2}{\Omega}cm$ and from 80 to 87%, respectively. The ZnO film deposited at 300 eV, and substrate temperature of $500^{\circ}C$ had the resistivity of $1.1{\times}10^{-4}{\Omega}cm$ and optical transmittance of 85% in visible range. As a result of experiments, we provides a suggestition that ZnO thin Films can be effectively used as the DSSC substrate Materials.

• 한국진공학회지
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• 제9권2호
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• pp.130-135
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• 2000

Photoluminescence(PL)와 photoreflectance(PR)를 이용하여 $Al_{0.25}/Ga_{0.75}/As/In_{0.15}/Ga_{0.85}$/AS/GaAS 슈우도형 고 전자 이동도 트랜지스터 구조에 대한 특성을 조사하였다. 온도 10K의 PL측정에서 InGaAs 양자우물에 의한 e2-hl 및 e2-hl 전이 피크가 각각 1.322 및 1.397 eV에서 관측되었다. 온도 의존성으로부터 첫번째 가전자 띠와 두번째 가전자 띠의 에너지 차이는 약 23'meV로 나타났다. 또한 300 K에서의 PR 측정으로 e2-h2및 e2-hl 전이에 의한 피크를 관측하였고, 두번째 전도 띠의 에너지 준위에 의한 피크가 띠 채움으로 인해 첫번째 전도 띠의 에너지 준위에 의한 피크보다 상대적으로 우세하였다. 반면에 PL 측정에서는 전자 가리개 효과 때문에 첫번째 전도 띠에 의한 피크가 우세하였다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제3권1호
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• pp.1-12
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• 2003

This paper describes a study on the abnormal behavior of the electrical characteristics of the (n)GaAs/Ti/Pt/Au Schottky contacts prepared by the two techniques of electron beam deposition and rf sputtering and after an annealing treatment. The samples were characterized by I-V and C-V measurements carried out over the temperature range of 150 - 350 K both in the as prepared state and after a 300 C, 30 min. anneal step. The variation of ideality factor with forward bias, the variation of ideality factor and barrier height with temperature and the difference between the capacitance barrier and current barrier show the presence of a thin interfacial oxide layer along with barrier height inhomogenieties at the metal/semiconductor interface. This barrier height inhomogeneity model also explains the lower barrier height for the sputtered samples to be due to the presence of low barrier height patches produced because of high plasma energy. After the annealing step the contacts prepared by electron beam have the highest typical current barrier height of 0.85 eV and capacitance barrier height of 0.86 eV whereas those prepared by sputtering (at the highest power studied) have the lowest typical current barrier height of 0.67 eV and capacitance barrier height of 0.78 eV.

• 한국재료학회지
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• 제15권6호
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• pp.361-369
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• 2005

InP(100) crystal surface was irradiated by ion beams with low energy $(180\~225\;eV)$ and high flux $(\~10^{15}/cm^2/s)$, Self-organization process induced by ion beam was investigated by examining nano structures formed during ion beam sputtering. As an ion source, an electrostatic closed electron Hall drift thruster with a broad beam size was used. While the incident angle $(\theta)$, ion flux (J), and ion fluence $(\phi)$ were changed and InP crystal was rotated, cone-like, ripple, and anistropic nanostrucuture formed on the surface were analyzed by an atomic force microscope. The wavelength of the ripple is about 40 nm smaller than ever reported values and depends on the ion flux as $\lambda{\propto}J^{-1/2}$, which is coincident with the B-H model. As the incident angle is varied, the root mean square of the surface roughness slightly increases up to the critical angle but suddenly decreases due to the decrease of sputtering yield. By the rotation of the sample, the formation of nano dots with the size of $95\~260\;nm$ is clearly observed.