http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Fabrication of a 50 nm half-pitch wire grid polarizer using nanoimprint lithography
Ahn, Seh-Won,Lee, Ki-Dong,Kim, Jin-Sung,Kim, Sang Hoon,Park, Joo-Do,Lee, Sarng-Hoon,Yoon, Phil-Won IOP Pub 2005 Nanotechnology Vol.16 No.9
<P>We report the fabrication of a 50 nm half-pitch wire grid polarizer with high performance using nanoimprint lithography. The device is a form of aluminium gratings on a glass substrate whose size of 5.5 cm × 5.5 cm is compatible with a microdisplay panel. A stamp with a pitch of 100 nm was fabricated on a silicon substrate using laser interference lithography and sidewall patterning. The imprint and the aluminium etching processes are optimized to realize uniform aluminium gratings with aspect ratio of 4. The polarization extinction ratio of the fabricated device is over 2000, with transmission of 85% at a wavelength of 450 nm, which is the highest value ever reported. This work demonstrates that nanoimprint lithography is a unique cost-effective solution for nanopatterning requirements in consumer electronics components. </P>
나노 임프린트 기술을 이용한 폴리머 도파로 기반의 브래그 격자형 파장 필터
安世源(Seh-Won Ahn),李起東(Ki-Dong Lee),金都煥(Do-Hwan Kim),陳元準(Won-Jun Chin),李相信(Sang-Shin Lee) 대한전기학회 2006 전기학회논문지C Vol.55 No.5
A polymeric waveguide-type wavelength filter based on a Bragg grating has been proposed and fabricated using the simple nanoimprint technique, for the first time to our knowledge. An ultraviolet transparent stamp with the single-mode waveguide pattern incorporating a surface-relief-type Bragg grating was specially designed selective dry-etching process. Using this stamp, the device fabrication was substantially involving just a single-step process of imprint followed by polymer spin-coating. The achieved maximum reflection was higher than 25 ㏈ at the center wavelength of 1569 ㎚. And the 3-㏈ bandwidth was 0.8 ㎚ for the device length of 1.5 ㎝.
Jenny H. Shim,Seh-Won Ahn,Heon-Min Lee 한국물리학회 2013 Current Applied Physics Vol.13 No.7
We observe >6% efficiency enhancement in silicon thin film solar cell using a p-type microcrystalline silicon oxide (mc-SiO:H) contact layer between transparent conducting oxide (TCO) electrode and the hydrogenated amorphous silicon (a-Si:H) layer. The role of the above contact layer is to reduce the Schottky barrier effect as well as the hetero-junction barrier formation at the interface. Despite its nanometer scale thickness, the properties of the contact layer significantly affect the solar parameters. Based on our results, p-type doped mc-SiO:H can be an ideal material as a contact layer due to its good optical response without noticeable degradation in its electrical property.
Surface morphology evolution of microcrystalline silicon p-layer prepared by RFPECVD
Seung-Yoon Lee,Seh-won Ahn,Heon-Min Lee 한국물리학회 2010 Current Applied Physics Vol.10 No.2
Surface morphology and crystallinity of silicon p-layer have been investigated on the effect of various deposition conditions of RFPECVD in order to clarify crystalline nuclei evolution. Crystallinity increased with increasing hydrogen dilution, but decreased with increasing both RF input power and diborane doping. Microcrystalline nuclei size increased with increasing working pressure, RF input power and substrate temperature. However, surface morphology was not correlated with crystallinity or deposition rate. A film with relatively large nuclei but having rather low crystallinity can be prepared for some condition,and vice versa. In order to get a dense microcrystalline silicon intrinsic layer subsequently deposited,surface morphology control of microcrystalline p-layer seems to be important as well as crystallinity.
윤상수(Sang-Soo Yoon),안세원(Seh-Won Ahn),이성은(Sung-Eun Lee),박주도(Joo-Do Park),김진성(Jin-Sung Kim),이기동(Ki-Dong Lee) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
We have demonstrated a nanowire polarizer fabricated by the nanoimprint lithography. The nanowire polarizer is a form of an aluminum grating with a period of 200 ㎚ on a glass substrate. The polymer resist pattern for metal etching process was formed by the nanoimprint lithography with a silicon-oxide stamp, which was made by the laser interference lithography and the reactive ion etching. The polarization extinction ratio of the fabricated device is measured to be -38 ㏈ at 1550 ㎚. The nanoimprint lithography is a promising and cheap way to fabricate subwavelength-period optical elements.
Tandem cell 적용을 위한 narrow band gap을 갖는 a-Si 태양전지 개발
김선호(Kim, Sunho),유동주(You, Dongjoo),안세원(Ahn, Seh-Won),이헌민(Lee, Heonmin),김동환(Kim, Donghwan) 한국신재생에너지학회 2010 한국신재생에너지학회 학술대회논문집 Vol.2010 No.06
실리콘 박막 태양전지의 효율을 향상시키기 위해 밴드갭이 다른 흡수층을 적용한 tandem형 적층 태양전지를 이용하고 있다. 일반적으로 1.7eV이상의 밴드갭이 큰 비정질 실리콘을 이용하여 단파장의 빛을 흡수하고, 상대적으로 낮은 1.1eV 정도의 밴드갭을 갖는 미세결정 실리콘 층으로 장파장을 흡수하게 된다. 이렇게 연결된 tandem형 태양전지의 효율을 극대화하기 위해서는 각 태양전지에서 발생하는 전류 밀도를 일치시키는 것이 필요하다. 이를 위해 비정질 실리콘의 두께가 증가되는 경우가 있는데 이러한 경우 비정질 실리콘의 광열화 특성(Lihgt-induced degradation)으로 안정화 효율이 감소하게 된다. 따라서 비정질 실리콘 태양전지의 전류 밀도를 향상 시켜 두께를 최소화하는 것이 매우 중요하다. Tandem형 태양전지에서 비정질 실리콘 태양전지의 전류 밀도를 향상시키기 위해 두 개의 전지사이에 광 반사층을 적용하여 태양전지를 제조하게 된다. 이러한 경우 비정질 실리콘의 전류 밀도는 증가하지만, 광 반사 층의 장파장 흡수로 인하여 하부 태양전지의 전류 밀도 감소가 더 커지게 되어 전체 발생 전류 밀도는 오히려 감소하게 된다. 본 논문에서는 비정질 실리콘의 밴드갭을 제어하여 광 흡수 파장 영역 확대로 전류 밀도를 향상시키는 연구를 진행하였다. PECVD의 RF power 조건을 제어하여 1.75eV에서 1.67eV까지 밴드갭을 변화시켰다. 이와 같은 조건의 박막을 광 흡수층으로 갖는 p-i-n 구조의 비정질 실리콘 태양전지를 제작하였다. i층의 밴드갭이 감소됨에 따라 장파장 영역의 흡수가 확대되어 전류 밀도가 증가 하였지만, Voc의 감소가 컸다. 이는 i층의 밴드갭이 좁아짐에 따라 p층과의 불연속성이 커졌기 때문이다. 이러한 악영향을 줄이기 위해 p층과 i층 사이에 buffer층을 삽입하여 태양전지를 제작하였다. 이와 같은 최적의 buffer층 삽입을 통하여 불연속성을 줄임으로써 Voc의 상승효과를 확인하였다. 본 연구의 결과로 좁은 밴드갭을 갖는 광 흡수 층을 적용하여 전류 밀도를 향상시키고, 최적화된 buffer층 삽입으로 Voc를 향상시킴으로써 고효율의 비정질 실리콘 태양전지를 제작하였다. 이를 tandem형 태양전지에 적용할 경우 초기 효율뿐만 아니라 얇은 두께에서 제조할 수 있기 때문에 광열화 특성이 향상되어 안정화 효율의 증가를 가져올 수 있다.
Soohyun Kim,Hongcheol Lee,Jin-Won Chung,Seh-Won Ahn,Heon Min Lee 한국물리학회 2013 Current Applied Physics Vol.13 No.4
Light trapping is a key issue in improving the efficiency of thin-film Si solar cells, and using a back reflector material plays a critical role in improving a cell’s light-trapping efficiency. In this study, we developed n-type microcrystalline silicon oxide (n-mc-SiOx) films that are suitable for use as back reflectors in thin-film silicon solar cells. They exhibit a lower refractive index and lower absorption spectra, especially at long wavelengths of >700 nm, than conventional ZnO:Al materials, which are beneficial for this application. The n-mc-SiOx films were prepared by the PECVD (plasma-enhanced chemical vapor deposition) method and applied to the fabrication of back reflectors in mc-Si:H solar cells. We also characterized the changes in cell performance with respect to the refractive index, conductivity,and thickness of the n-mc-SiOx back reflectors. The novel back reflector boosts the total current density by up to 3.0% with the help of the enhanced long-wavelength response. It also improves open circuit voltage (Voc) and fill factor (FF), which may be attributed to the reduced shunt current caused by the anisotropic electrical characteristics of the n-mc-SiOx layer. Finally, we could achieve a conversion efficiency for the hydrogenated microcrystalline silicon (mc-Si:H) solar cells of up to 9.3% (Voc: 0.501 V, Jsc: 27.4 mA/cm2, FF:0.68) using the n-mc-SiOx back reflector.
Yun-Seong Lee,인정환,Seung-Kyu Ahn,Sang-Hun Seo,Dong-Joo You,Seh-Won Ahn,Heon-Min Lee,장홍영 한국물리학회 2010 Current Applied Physics Vol.10 No.2
We measured the trend of the electron temperature in the SiH4/H2 plasma by monitoring the optical emission intensity ratio between Si* (288 nm) and SiH* (414 nm) and estimated the averaged electron density through plasma impedance measurement with a current–voltage monitor (ENI.INC, V–I probe). The plasma was generated between parallel plates by using VHF (40.68 MHz) power for Plasma Enhanced Chemical Vapor Deposition (PECVD). For various pressures and input powers, we analyzed the relation between the plasma parameters and the characteristics of the H2-diluted silane plasma. From the analysis,the optimization of the lc-Si:H CVD process was suggested.