• Proceedings of the Korean Vacuum Society Conference
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• 2010.02a
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• pp.62-62
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• 2010

근래 실리콘 나노선을 이용한 FET타입의 바이오 센서로의 응용 연구가 활발하다. 본 연구에서는 top-down 방식으로 제작한 실리콘 나노선의 전자수송 특성을 측정 분석하여 실리콘 나노선의 기하학적 변수에 따른 수송 변수를 추출하였다. 두께가 40 nm인 SOI wafer로부터 출발하여 일반적인 포토리소그라피와 건식식각 공정을 통하여 선폭이 100-300 nm 그리고 길이가 2-20 mm인 실리콘 나노선을 제작하고 resistance 및 transconductance를 측정하여 전하농도와 이동도의 선폭에 대한 의존도를 얻었다. 이를 바탕으로 bare surface, OH-activated surface, APTES-treated surface등 실리콘 표면상태에 따른 표면전하의 시간에 대한 진화과정을 모니터 할 수 있었으며, 또한 PBS 용액상태에서 pH를 변화시킴에 따른 전하수송 특성곡선의 변화를 연구하였다.

• Proceedings of the KAIS Fall Conference
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• 2003.06a
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• pp.113-115
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• 2003

우리가 타자기로 글을 쓸 때는 먹지리본을 햄머가 가격하여 종이 위에 글씨 청태의 먹이 묻는 원리로 진행된다. 이러한 원리를 미세 패터닝에 응용하여, 해머 역할을 하는 Nd-YAG 레이저로 유리기판/100nm Cr(먹지)// 실리콘기판 (종이) 구조의 적충물에 조사시켜 Cr이 실리콘기판 위에 전사됨으로써 미세 패터닝이 가능한지 확인하였다. 제안된 미세 패터닝은 TeraBit/in²급 고밀도 정보저장 또는 반도체 공정의 생산성 향상을 위해 응용이 가능하다. 선폭 50 ㎛급 레이저를 주사속도 200과 1500 ㎜/s, Q스위치 조건을 10,000～50,000 ㎐로 변화시키며 마킹을 실시한 결과 Cr의 전사는 진행되지 않았으나, 최종적으로 입사 선폭의 33％ 이하로 마킹이 가능하여 비싼 광학계를 가진 레이저를 대치하여 보다 정말한 마킹이 가능함을 확인하였다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.160-160
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• 2003

• Proceedings of the Optical Society of Korea Conference
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• 2005.07a
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• pp.230-231
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• 2005

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.205-206
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• 2006

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2003.04a
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• pp.53-53
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• 2003

• Proceedings of the Optical Society of Korea Conference
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• 1997.08a
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• pp.75-75
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• 1997

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.7
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• pp.3474-3481
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• 2013

In this work, a new high frequency transmission line structure combined with defected ground structure (DGS) and artificial dielectric substrate (ADS) structure is proposed. DGS patterns give add the additional inductance to transmission lines and results in the increased characteristic impedance for a given line width. To the contrary, ADS presents increased capacitance and reduced line impedance. So both play a role in reducing the length of transmission lines commonly, but in preserving the line impedance complementarily. This means that the length of transmission lines can be reduced furtherly by DGS and ADS without a critical change of line width compared to the cases when one of DGS and ADS is used only. As examples, $35{\sim}100{\Omega}$ transmission lines having DGS and ADS are designed, fabricated, measured, and compared to the simulation results. A good agreement between the simulated and measured line impedances is presented. In addition, the physical lengths of the proposed transmission lines are only 55.4~76.9% of those of the normal microstrip lines for the same electrical lengths.

• Journal of the Korean Magnetics Society
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• v.24 no.5
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• pp.135-139
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• 2014

Iron-oxide nanopowders were synthesized by a pulsed wire evaporation (PWE) in various ambient gas conditions. SEM measurement indicates that the spherical iron nanoparticles are about 50 nm in diameter. The phase analysis for the produced iron-oxide powders was systematically investigated by using $M\ddot{o}ssbauer$ spectra and the results show that classified phases of $Fe_2O_3$ and $Fe_3O_4$ can be controlled by regulating the oxygen concentration in the mixed gas during the PWE process. A quadrupole line on the center of $M\ddot{o}ssbauer$ spectrum represents the superparamagnetic phase of 12 % from ${\gamma}-Fe_2O_3$ phase.

• Korean Journal of Optics and Photonics
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• v.10 no.2
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• pp.162-168
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• 1999

A new design of four-pass dye laser amplifier affording a narrow-bandwidth pulsed output is demonstrated to suppress the amplified spontaneous emission(ASE) carried by the amplifier output and reduce the possibility of parasitic oscillation in the amplifier. By the direct pulsed amplification of a cw 100 mW dye laser under a Q-switched doubled Nd:YAG laser pumping with energy of 5.6 mJ/pulse, high-peak-power pulsed output with 1.5-mJ energy in 130-MHz bandwidth is obtained corresponding to a power gain greater than $2{\times}10^6$ and an energy efficiency of 27%. The ASE ratio in the four-pass amplifier output is dramatically reduced by using a diffraction grating in the amplifier. Compared with the results obtained from the normal operation of the amplifier with no frequency-selective device, the ASE ratio is reduced by a factor in excess of 10 to remain under 1.5% of the amplifier output whereas the total output energy is slightly increased by ~4%.