• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.298-299
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• 2011

최근 입력소자로 활용되는 터치스크린은 키보드나 마우스와 같은 입력장치를 사용하지 않고, 스크린에 손가락, 펜 등을 접촉하여 입력하는 방식이다. 터치패널의 구현방식에 따라 저항막(Resistive) 방식, 정전용량(Capacitive) 방식, SAW (Surface Accoustic Wave; 초음파) 방식, IR (Infrared; 적외선) 방식등으로 구분된다. 특히 최근 관심을 받고 있는 IR 방식은 적외선이 사람의 눈에는 보이지 않으나, 직진성을 가지고 있어 장애물이 있으면 차단되는 특성을 이용한 방식이다. IR방식의 터치패널은 발광(Light emitting)소자와 수광(Light detecting)소자가 마주하도록 배치되어 터치에 의해 차단된 좌표를 인식하게 되며, ITO 필름 등이 필요 없어 Glass 1장으로도 구현이 가능하며 투과율이 우수하다. 이러한 IR 방식의 터치패널을 제작하기 위하여 사용된 IR 광검출기는 광학적 band-gap이 작은 박막물질을 필요로 한다. 본 연구에서는 IR 광검출을 위한 물질로 SiGe를 co-sputtering 기법을 이용하여 성장시켰다. 일반적으로 SiGe 박막을 성장시키기 위하여 저압화학기상증착법(low pressure chemical vapor deposition, LPCVD)이나 고진공 LPCVD를 사용하지만 본 연구에서는 CVD에 비하여 무독성이면서 환경친화적이고 초기투자비용이 낮은 증착장비인 sputtering을 이용하였다. 본 연구에서 성장된 SiGe 박막은 400$^{\circ}C$에서 rf plasma가 인가된 Ge과 dc plasma가 인가된 Si의 power를 조절하여 결정화도가 70% (Fig. 1)이고 결정성장방향이 (111)과 (220)방향으로 성장하는 SiGe 박막을 얻을 수 있었다. 본 논문에서는 co-sputtering 성장조건에 따라 성장된 SiGe의 박막 특성을 논의할 것이다.

• 태양에너지
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• 제5권2호
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• pp.46-53
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• 1985

Hydrogenated amorphous silicon solar cells which are fabricated by photo-chemical vapor deposition (photo-CVD) system has been investigated. In the photo-CVD system which consists of three separate reaction chambers, low-pressure mercury lamp has been used as a light source. The main reactant ($Si_2H_6/He$) gases which are premixed with a small amount of mercury vapor in a mercury-vaporizer kept at $50^{\circ}C$ have been used. Using $C_2H_2$ and $SiH_2(CH_3)_2$ as the carbon source, p-type wide band gap a-SiC:H films have been obtained. The result has been found that the undoped layers of the pin/substrate solar cells are influenced by the residual impurities, such as phosphorus and boron during the deposition process. By minimizing the effect of the impurities in the i-layer and optimizing conditions at the p-layer and p/i interface, the energy conversion efficiency of 9.61 % under AM-1 ($100mW/Cm^2$) has been achieved for pin/substrate solar cells illuminated through their p-layers, using the three separate reaction chamber apparatus. It is expected that a-SiC:H solar cells with the energy conversion efficiency over 10% have been fabricated by Photo-CVD method.

• 한국표면공학회지
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• 제43권4호
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• pp.194-198
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• 2010

Indium doped zinc oxide films (ZIO) were deposited on non-alkali glass substrates by radio frequency (RF) magnetron sputtering at room temperature. The structural, electrical and optical properties of the ZIO films were investigated as a function of their $In_2O_3$ content (3.33-15.22 wt%). The ZIO films deposited with an $In_2O_3$ content of 9.54 wt% showed a relatively low resistivity of $9.13{\times}10^{-4}{\Omega}cm$ and a highly c-axis preferred orientation. The grain size and FWHM were mainly affected by the $In_2O_3$ content. The crystallinity and resistivity were enhanced with increasing grain size. The average transmittance of the ZIO films was over 85% in the visible region and their band gap varied from 3.22 to 3.66 eV depending on their doping ratio.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 춘계학술대회
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• pp.691-692
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• 2016

본 논문은 802.11a 무선 랜용 5.25-GHz BiCMOS 저 잡음 증폭기를 제안한다. 이러한 회로는 1볼트 전원에서 동작하며, 저 전압 전원 공급에서도 높은 전압 이득을 가지도록 설계하였다. 제안한 회로는 $0.18{\mu}m$ SiGe HBT BiCMOS로 설계되어 있다. 저 전압 및 저 전력 동작을 위해 바이어스 회로는 밴드 갭 참조 (band-gap reference circuit) 바이어스 회로를 사용하였다. 제안한 회로는 최근 발표된 연구결과에 비해 높은 전압이득, 낮은 잡음지수 및 작은 칩 크기 특성을 보였다.

• 전력전자학회논문지
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• 제20권6호
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• pp.558-565
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• 2015

Gallium nitride high-electron mobility transistor (GaN HEMT) is the strongest candidate for replacing Si MOSFET. Comparing the figure of merit (FOM) of GaN with the state-of-the-art super junction Si MOSFET, the FOM is much better because of the wide band gap characteristics and the heterojunction structure. Although GaN HEMT has many benefits for the power conversion system, the performance of the power conversion system with the GaN HEMT is sensitive because of its low threshold voltage ($V_{th}$) and even lower parasitic capacitance. This study examines the characteristics of a phase-shifted full-bridge dc-dc converter with cascode GaN HEMT. The problem of unoptimized dead time is analyzed on the basis of the output capacitance of GaN HEMT. In addition, the printed circuit board (PCB) layout consideration is analyzed to reduce the negative effects of parasitic inductance. A comparison of the experimental results is provided to validate the dead time and PCB layout analysis for a phase-shifted full-bridge dc-dc converter with cascode GaN HEMT.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.1437-1439
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• 2009

Electrical and optical properties of $SiO_2$-doped ZnO (SZO) films on the corning 7059 glass substrates by using rfmagnetron sputtering method are investigated. The deposition rate becomes maximum near 3 wt.% and gradually decreases when the $SiO_2$ content further increases. The growth rates at 3 wt.% is $4^{\circ}$A/s. We found that the average transmittance of all films is over 80% in the wavelength range above 500 nm. The optical band gap decreases from 3.52 to 3.33 eV with an increase in thickness. X-ray diffraction patterns show that the film with a relatively low $SiO_2$ content (< 4 wt.%) is amorphous. SZO films at the $SiO_2$ contents of 2 wt.% shows the resistivity of about $3.8{\times}10^{-3}{\cdot}cm$. The sheet resistance decreases with increasing the heat treatment temperature.

• Advances in nano research
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• 제3권2호
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• pp.81-96
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• 2015

Octahedral shaped single crystalline undoped and Ga-doped indium oxide nano-and microcrystals were fabricated using vapor-solid growth process. Effects of Ga doping on the crystallinity, defect structure, and optical properties of the nano-/microstructures have been studied using scanning electron microscopy, microRaman spectroscopy, transmission electron microscopy and cathodoluminescence spectroscopy. It has been observed that incorporation of Ga does not affect the morphology of $In_2O_3$ structures due to its smaller ionic radius, and similar oxidation state as that of In. However, incorporation of Ga in high concentration (~3.31 atom %) causes lattice compression, reduces optical band gap and defect induced CL emissions of $In_2O_3$ nano-/microcrystals. The single crystalline Ga-doped, $In_2O_3$ nano-/microcrystals with low defect contents are promising for optoelectronic applications.

• Journal of Electrical Engineering and Technology
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• 제7권6호
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• pp.965-970
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• 2012

Structure and optical properties of cadmium sulphide-zinc oxide composite nanorods have been evaluated by suitable characterization techniques. The X-ray diffraction spectrum contains a series of peaks corresponding to reflections from various sets of lattice planes of hexagonal ZnO as well as CdS. The above observation is supported by the Micro-Raman spectroscopy result. The optical reflectance spectra of CdS-ZnO is compared with that of ZnO where we observe an enhanced absorption and hence diminished reflection from CdS-ZnO compared to that from only ZnO. A very small intensity of the visible photoluminescence peak observed at 550 nm proves that the ZnO nanorods have very low concentrations of point defects such as oxygen vacancies and zinc interstitials. The photocurrent in the visible region has been significantly enhanced due to deposition of CdS on the surface of the ZnO nanorods. CdS acts as a visible sensitizer because of its lower band gap compared to ZnO.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2011년도 춘계학술대회 및 Fine pattern PCB 표면 처리 기술 워크샵
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• pp.108-109
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• 2011

유기태양전지를 제작 시에 요구되는 것 중 하나는 active layer의 thermal annealing이다. Thermal thermal annealing 없이는 P3HT의 self-organization이 잘 이뤄지지 않아 비정질의 모습을 보인다. 또한 low band-gap이나 열에 취약한 물질을 사용 시에 태양전지 효율이 낮아지게 된다. 이 점을 착안하여 Active layer에 사용되는 유기용매의 solvent vapor pressure 차이를 이용하여 co-solvent가 되도록 mixing하여, co-solvent로 poly(3-hexylthiopene)(P3HT):[6,6] - phenyl $C_{61}$-butyric acid methyl ester (PCBM)를 blending 하여 active layer로 사용하였으며, 유기태양전지 디바이스 제작 결과 thermal thermal annealing 없이 2.8%까지 도달하였다. X-Ray Diffraction(XRD)과 Atomic Force Microscopy(AFM)를 통하여 P3HT의 결정화가 이루어 졌음을 확인하고 이를 통해 active layer의 thermal annealing이 없이도 P3HT의 self-organization이 이뤄짐을 알 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 C
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• pp.1890-1892
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• 2005

Recently, high luminance and high efficiency were realized in OLEDs with multilayer structure including emitting materials such as metal-chelate complexes. New luminescent materials, [2- (2-hydroxyphenyl)-quinoline] (Zn(HPB)q), [(1,10-phenanthroline)- (8-hydroxyquinoline)] Zn(Phen)q was synthesized. Zn-Complexes have low molecular compound and thermal stability. The ionization potential(IP) and electron affinity(EA) of Zn-complexes were measured by cyclic-voltammetry(CV). The fundamental structure of the OLEDs was $ITO/{\alpha}$-NPD/Zn-Complex/Al and then we made device structure rightly in energy band gap. We using Zn(Phen)q as emitting layer and Zn(HPB)q as electron transport layer. We measured current density-voltage, luminance-voltage characteristics.