• Transactions on Electrical and Electronic Materials
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• 제12권5호
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• pp.204-208
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• 2011

In this paper, the design area of a fabricated solar cell has been analyzed with respect to its charge density. The mathematical calculation used for charge-density derivation was obtained from the 2001 version of a MATHCAD program. The parameter range for the calculations was ${\pm}1{\times}10^{17}cm^{-3}$, which is in the normal parameter range for n-type doping impurities ($7.0{\times}10^{17}cm^{-3}$) and also for p-type impurities ($4.0{\times}10^{17}cm^{-3}$). Therefore, it can be said that the fabricated solar-cell design area has a direct effect on charge-density changes.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.343-344
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• 2008

A surface micromachined uncooled microbolometer based on the amorphous silicon was designed, fabricated, and characterized. We designed the microbolometer with a pixel size of $44\times44{\mu}m^2$ and a fill factor of about 50 % ~ 70% by considering such important factors as the thermal conductance, thermal time constant, the temperature coefficient of resistance, and device resistance. Also, we successfully fabricated the microbolometer by using surface MEMS technology. Finally, we investigated responsivity and detectivity properties depends on the active area size.

• Current Optics and Photonics
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• 제1권5호
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• pp.544-550
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• 2017

This simulation based study reports a novel tunable, compact, room temperature terahertz (THz) transistor source, operated on the concept of charge plasma oscillation with the capability of radiating within a terahertz gap. A vertical cavity with a quasi-periodic distributed-Bragg-reflector has been attached to a THz plasma wave transistor to achieve a monochromatic coherent surface emission for single as well as multi-color operation. The resonance frequency has been tuned from 0.5 to 1.5 THz with the variable quality factor of the optical cavity from 5 to 290 and slope efficiency maximized to 11. The proposed surface emitting terahertz transistor is able to satisfy the demand for compact solid state terahertz sources in the field of teratronics. The proposed device can be integrated with Si CMOS technology and has opened the way towards the development of silicon photonics.

• 한국광학회지
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• 제28권1호
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• pp.9-15
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• 2017

실리콘 기판으로 만든 바이오센서에서 펩타이드-항체의 접합 동특성을 회전 타원분광계로 정밀하게 측정하고 분석하였다. 극도로 낮은 몰농도의 펩타이드를 측정할 때, 시료가 놓이는 바이오센서의 표면의 불완전한 편평도와 완충용액 굴절률 변화로 인한 측정오차를 줄이기 위하여 금속박막의 유리 프리즘 대신에 실리콘 기판 위에 덱스트란 SAM을 직접 적층하여 바이오센서를 만들었다. $100{\mu}l/min$의 완충용액 주입속도에서 바이오센서에 올려진 항체 및 펩타이드의 접합특성을 각각 측정하였다. 리터당 5 ng의 낮은 항체농도에서도 항체-덱스트란 SAM 사이의 동특성을 쉽게 측정할 수 있었다. 또한 100 nM까지의 펩타이드에 대한 미세한 흡착 및 해리 특성을 정밀하게 측정할 수 있었으며, 접합 동특성 식에 이 실험결과를 피팅하여 흡착계수와 해리계수를 구할 수 있었다. 이 결과로부터 펩타이드의 평형상태의 해리상수인 $K_D$는 97 nM이었고, 이 수치는 Class I에 속함을 알 수 있었다.

• 한국정밀공학회지
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• 제27권7호
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• pp.117-122
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• 2010

Recently, aspheric glass lens molding core is fabricated with tungsten carbide(WC). If molding core is fabricated with silicon carbide(SiC), SiC coating process, which must be carried out before the Diamond-Like Carbon(DLC) coating can be eliminated and thus, manufacturing time and cost can be reduced. Diamond Like Carbon(DLC) is being researched in various fields because of its high hardness, high elasticity, high durability, and chemical stability and is used extensively in several industrial fields. Especially, the DLC coating of the molding core surface used in the fabrication of a glass lens is an important technical field, which affects the improvement of the demolding performance between the lens and molding core during the molding process and the molding core lifetime. Because SiC is a material of high hardness and high brittleness, it can crack or chip during grinding. It is, however, widely used in many fields because of its superior mechanical properties. In this paper, the grinding condition for silicon carbide(SiC) was developed under the grinding condition of tungsten carbide. A silicon carbide molding core was fabricated under this grinding condition. The measurement results of the SiC molding core were as follows: PV of 0.155 ${\mu}m$(apheric surface) and 0.094 ${\mu}m$(plane surface), Ra of 5.3 nm(aspheric surface) and 5.5 nm(plane surface).

• 한국광학회지
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• 제16권2호
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• pp.113-120
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• 2005

LCD-BLU(liquid crystal device-back light unit)에 사용되는 도광판의 미세 산란패턴을 만드는 새로운 방법으로서, 실리콘 웨이퍼의 비등방 식각에 의해 자연적으로 형성되는 3차원 결정면 구조를 이용하는 방법을 제안하였다. 실리콘 3차원 결정면을 갖는 도광판과 프리즘 시트의 원판을 설계 및 제작하였고, casting 공정을 통해 PDMS 재질로 복제된 도광판을 제작하여 특성을 분석하였다. 측정 결과, 기존 인쇄형 도광판에 비해 실리콘피라미드 패턴의 도광판이 $10\%$ 증가된 정면 휘도 효율을 가질 수 있음을 실험적으로 검증하였다.

• 한국광학회지
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• 제24권2호
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• pp.92-98
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• 2013

회전검광자 방식의 타원계 구조에 기초하여 두꺼운 막들 내부에서 일어나는 다중반사에 인한 빛의 세기를 결맞지 않도록 중첩함으로써 결맞음길이보다 두꺼운 막 두 개가 다층박막시료 위에 있을 때 적용되는 타원상수 표현들을 유도하였다. 유도된 표현들을 커버유리와 공기층 아래에 있는 산화규소 박막이 코팅되어 있는 시료의 타원법 분석에 적용하여 그 유용성을 확인하였다.

• Current Optics and Photonics
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• 제4권6호
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• pp.551-557
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• 2020

A mirror-in-slab waveguide is fabricated on a slab waveguide by using the refractive-index contrast between two materials, with the reflection performance depending on the slab waveguide's design. In this research, a slab waveguide design consisting of silicon (Si) as the core and SiO2 as the substrate was designed and developed to determine the coupling, waveguide, and mirror losses. Based on experimental results, coupling loss is dominant and is affected by the design of the slab waveguide. Furthermore, the mirror loss is affected by the design of the mirror, such as the curvature radius and the size of the mirror. TE and TM polarizations of light are used in the measurements. The experimental results show that mirror losses due to reflection by mirrors are 0.011 dB/mirror and 0.007 dB/mirror for TE and TM polarizations respectively. A simulation was performed to confirm whether the size of mirror is sufficient to reflect the input light, and to check the quality of the surfaces of fabricated mirrors.

• Current Optics and Photonics
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• 제6권1호
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• pp.60-68
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• 2022

We report on the design of the secondary and the tertiary mirrors used in lightweight assemblies made entirely of silicon carbide (SiC). The essential design points are weight reduction within the acceptable deformation of the mirror surface by gravity release, temperature change, and vibration during or after space launch. To find a design that achieves the target requirements, we established finite element models for various candidate designs and subjected each one to wave front error analyses along gravity directions and in operation temperatures. We also calculated the natural frequencies of the candidate assemblies. Our study suggested that a triangular cell with bipod flexure support can satisfy the target weight within the requirements.

• Current Optics and Photonics
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• 제8권4호
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• pp.399-405
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• 2024

In this paper, an optical modulator based on monolayer graphene and triple-layer black phosphorus (BP) heterojunction in the optical communication band range is designed. The influences of geometric parameters, chemical potential, BP orientation and dispersion on the fundamental mode of this modulator were determined in detail by the finite-difference time-domain (FDTD) method. Using appropriate geometric parameter settings, the extinction ratio of this proposed modulator is 0.166 dB, while the modulator with a working length of 3 ㎛ can realize a 0.498 dB modulation depth. The 3-dB bandwidth of this modulator could achieve up to 2.65 GHz with 27.23 fJ/bit energy consumption. The extinction ratio and bandwidth of the proposed modulator increased by 66% and 120.83%, respectively, compared to the monolayer graphene-based ridge-type waveguide modulator. Energy consumption was reduced by 97.28%, compared to a double-layer graphene-based modulator.