• Journal of Magnetics
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• 제12권2호
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• pp.77-80
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• 2007

Recently there was a proposal for a spin filter by using the spin superlattice structure. In a certain energy range, the proposed structure exhibits a high spin filtering efficiency close to 100%. Unfortunately such energy range turns out to be narrow. In this paper, we report a method to widen the energy range by using an analogy to optical anti-reflection coating. In optics, it is well known that a stack of alternating layers of two dielectric materials can function as a highly transmissive or reflective filter for wide range of wavelength. Since electrons also have wave character as light, it would be possible to make an electronic analog of an optical filter. We demonstrate that alternating layers of two materials with different g-factors can function as a spin filter that allows electrons to be transmitted only when their spins point towards a certain particular direction. This spin-superlattice-based spin filter operates in wide energy ranges, curing the problem in the previous proposal.

• 한국안광학회지
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• 제6권2호
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• pp.31-35
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• 2001

$TiN_xW_y$ 전도박막층으로 무반사, 무정전 광학박막을 Essential Macleod 프로그램을 이용하여 설계한 결과 [공가 ${\mid}TiN_xW_y{\mid}SiO_2{\mid}$ 유리]층은 단 두층코팅막으로 가시광선 파장영역 (450~700 nm)에서 넓게 AR 코팅이 되었다. RF magnetron 스퍼터링 장치에 질소가스와 아르곤가스를 동시에 주입하면서 Ti 타켓을 스퍼터링하여 $TiN_x$ 광학박막을 7 nm에서 10 nm의 두께로 유리기판 위에 제작하였다. 이 때 박막의 화학적 조성과 성분비를 분석하기 위해 XPS를 사용하였고, 박막의 면저항과 화화적 조성과의 관계를 분석하기 위하여 XPS depth profiling과 4점탐침법을 사용하였다.

• 한국진공학회지
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• 제21권1호
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• pp.22-28
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• 2012

건물일체형 태양전지는 투명 연료감응형 태양전지 기술을 중심으로 연구개발이 진행되고 있다. 신뢰성-수율 개선 및 대면적화의 필요성 때문에 잘 정립된 박막 공정 기술에 기초하는 Si계 박막 태양전지가 건물일체형 태양전지를 구현할 기술로서 새롭게 조명 받고 있다. Si계 박막 태양전지에 선택적 투과막을 적용하면 가시광선은 태양전지를 투과하고 적외선은 광흡수층으로 반사되기 때문에 투명 태양전지의 변환효율이 향상된다. 본 연구에서는 선택적 투과막의 증착 기술로서 생산성 측면에서 유리한 스퍼터 증착을 이용하여 AlTiO 선택적 투과막을 형성하고 증착 조건을 조절하여 투과율을 향상시켰다.

• 한국안광학회지
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• 제3권1호
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• pp.237-242
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• 1998

$80SiO_2-20TiO_2$(mol%)의 무색투명한 비정질 박막을 현미경용 슬라이드 유리판과 사파이어 위에 tetraethyl orthosilicate와 titanium trichloride의 전구체 용액을 사용하여 스핀코팅방법으로 제조하였다. 코팅 후 $750^{\circ}C$에서 열처리된 박막은 높은 투과율과 낮은 반사율을 보였다. 슬라이드 유리판에 코팅한 $SiO_2-TiO_2$ 박막의 경우에 나트륨이온과 산소 간의 강한 상호작용에 의하여 고온과 높은 습도에서도 안정성이 우수하였다.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2011년도 춘계학술발표대회
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• pp.7.1-7.1
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• 2011

Nanoporous templates have been widely used for the development of new functional nanostructured materials suitable for electronics, optics, magnetism, and energy storage materials. We have prepared nanoporous templates by using thin films of mixtures of polystyrene-block-poly (methyl methacrylate) (PS-b-PMMA) and PMMA homopolymers. These templates have cylindrical nanoholes spanning the entire thickness of the film. Some applications of nanoporous templates are introduced: a) anti-reflective coating, b) the preparation of conducting polymer nanowires of poly (pyrrole), poly (3,4-ethylenedioxy-thiopene) onto a glass coated with indium-tin-oxide, and c) the separation membranes for biomaterials. We found that when the pore fraction of nanoholes in the film was ~0.68, almost zero reflectance at a specific wavelength, which can be changed with film thickness, was achieved at visible wavelengths Furthermore, ultra high density array of conducting nanowires was successfully prepared onto various substrates including flexible polymer. Due to highly alignment of polymer chain along the nanowire direction, the conductivity was much increased. Furthermore, these nanoporous films were found to be very effective for the separation of human Rhinovirus type 14 (HRV 14), major pathogen of a common cold in humans, from the buffer solution. We also found that when the pore size was effectively controlled down to 6 nm, a single file diffusion was observed.

• 한국진공학회지
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• 제8권4A호
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• pp.490-495
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• 1999

In 0.18 $\mu \textrm m$ LOGIC device, the etch rate of NMOS polysilicons is different from that of PMOS polysilicons due to the state of polysilicon to manufacture gate line. To control the etch profile, we tested the ratio of $Cl_2$/HBr gas and the total chamber pressure, and also we reduced Back He pressure to get the vertical profile. In the case of manufacturing the gate photoresist line, we used Bottom Anti-Reflective Coating (BARC) to protect refrection of light. As a result we found that $CF_4O_2$ gas is good to etch BARC, because of high selectivity and good photoresist line profile after etching BARC. in the results of the characterization of plasma damage to the antenna effect of gate oxide, NO type thin film(growing gate oxide in 0, ambient followed by an NO anneal) is better than wet type thin film(growing gate oxide in $0_2+H_2$ ambient).

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1825-1828
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• 2008

A simple method for the fabrication of porous nano-master for antireflective surface is presented. In conventional fabrication methods for antireflective surface, coating method with low refractive index has usually been used. However, it is required to have high cost and long times for mass production. In this paper, we suggested the fabrication method of antireflective surface by the hot embossing process using the porous nano patterned master on silicon wafer fabricated by low-temperature anodic aluminum oxidation. Through multi-AAO and etching processes, nano patterned master with high aspect ratio was fabricated at the large area. Pore diameter and inter-pore distance are about 150nm and from 150 to 200nm. In order to replicate anti-reflective structure, hot embossing process was performed by varying the processing parameters such as temperature, pressure and embossing time etc. Finally, antireflective surface can be successfully obtained after etching process to remove selectively silicon layer of AAO master.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.187-187
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• 2011

Nowadays, the issue of solar cell durability in local weather and environment is a crucial issue. Above all, surface corrosion on solar cell multilayers is a major factor that determines the durability of commercial solar cells; corrosive chemical interactions between air, humidity and chemical species and solar cell multilayers can unfavorably affect the durability. Here, we study microscopic and spectroscopic surface techniques to investigate the corrosive interaction on the antireflective layers of solar cell multilayers under various conditions such as acid, base, constant temperature and humidity. Surface morphology and adhesion force were characterized with atomic force microscopy before and after chemical treatment. Chemical composition, and transmittance factors were studied with X-ray photoelectron spectroscopy, and ultraviolet-visible spectroscopy, respectively. Based on these studies, we suggest the dominant factors in the corrosive chemical processes, and their influences on the structural, compositional, and optical properties of the antireflective layers.

• 한국전기전자재료학회논문지
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• 제32권4호
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• pp.281-286
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• 2019

Raman spectra of a-C:H thin films deposited with an unbalanced magnetron sputtering system showed that the G peak shifted to a higher wavenumber as the target power density increased and $I_D/I_G$ ratio increased from 0.902 to 1.012. Moreover, the transmittance of a-C:H films fabricated at 60 nm tended to decrease with increasing target power density; at 550 nm in the visible light region, the transmittance decreased from 69% to 58%. The rms surface roughness values of the a-C:H thin films decreased with increasing target power density, and varied from 1.11 nm to 0.71 nm. In order to achieve efficient light trapping, the light scattering at the rough interface must be enhanced. Consequently, the surface roughness of the thin film will decrease with the target power density. Further, the refractive index and reflectivity of the a-C:H thin films increased with increasing target power density; however, the Brewster angle decreased with the target power density. Hence, dye-sensitized solar cells using an a-C:H antireflective coating increased the CE, $V_{OC}$, and $J_{SC}$ by approximately 8.6%, 5.5%, and 4.5%, respectively.

• 한국안광학회지
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• 제19권4호
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• pp.471-477
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• 2014

목적: 국소 투과율 현미경을 이용하여 안경렌즈의 투과율 분포를 분석함으로써 렌즈의 광학적 균질성을 연구하고자 한다. 방법: 안경렌즈 표면에 집광된 레이저의 투과율을 광검출기와 락인앰프로 측정하고 그 결과를 분석하였다. 코팅되지 않은 렌즈와 멀티 코팅이 된 렌즈 그리고 누진렌즈가 시료로서 분석되었다. 결과: 누진렌즈와 물리적 자극이 가해진 렌즈의 측정 결과에서 국소 투과율 현미경 분석 결과가 광학 현미경을 통한 측정 결과와 높은 일치도를 보였다. 또한 광학적 결함이 있는 곳에서 투과율의 평균값은 감소하고 표준편차는 증가하였다. 자극이 가해지지 않은 렌즈에서는 반사방지 코팅의 유무가 투과율에 큰 영향을 미치는 것을 국소 투과율 현미경과 일반적 투과율 분석 모두에서 공통적으로 분석되었다. 결론: 시료에 다양한 자극이 가해졌을 때 투과율의 분포에 변화가 생김을 국소 투과율 현미경을 통해 확인하였다. 국소 투과율 현미경을 통한 이러한 분석은 렌즈 혹은 코팅막의 균일도를 평가 혹은 확인할 수 있는 하나의 방법으로 활용될 수 있다.