• 전자공학회논문지
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• 제53권8호
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• pp.76-82
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• 2016

본 논문에서는 근거리장에서 NFS(near field scanning)를 사용한 차폐효율 평가 방법을 통해 CNT(carbon nanotube) 필름의 차폐 특성을 분석하였다. 차폐 특성 평가는 농도 5%와 1mm의 두께를 가지는 CNT 필름과 실제 IC package를 모사한 테스트쿠폰을 사용하여 CNT 필름과 테스트쿠폰과의 거리에 따른 전자파 차폐효율 및 측정 위치에 따른 차폐효율을 측정하였다. 그 결과 근거리장에서 측정된 차폐효율은 주파수에 따라 차폐효율이 달랐다. 테스트쿠폰의 중심에서 측정된 전기장 차폐효율은 fringing effect의 영향을 받는 패턴경계보다 전기장 차폐효율이 좋은 것으로 측정되었다. 이는 근거리장에서 측정된 차폐효율은 주파수뿐만 아니라 CNT 필름과 측정 프로브의 높이, 측정 위치와 같은 측정 환경에 영향을 받는 것을 보여준다. 결론적으로 근거리장에서 제안된 방법을 사용하여 측정한 차폐효율과 ASTM D 4935-10에 의해 측정된 차폐효율은 연관성을 찾기 어렵기 때문에 전장 시스템의 거리 영역에 따라 적절한 측정 방법을 고려하여 측정해야 한다.

• 공업화학
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• 제33권2호
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• pp.188-194
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• 2022

본 연구에서는 비파괴적 표면 기능기화 통하여 단일벽 탄소나노튜브(SWCNT) 탄소소재의 특성 변화를 최소화 시킬 수 있는 대면적화 공법을 제안하고, 대면적화 된 SWNT 전자 필름 상에 효소를 집적하여 효소와 SWCNT 전자 필름 간 효율적 전자 전달을 연구하였다. p-terphenyl-4,4"-dithiol, dithiothreitol와 SWCNT의 혼합을 통해 SWCNT 전자 필름의 균일도 및 전하 전달 능력을 향상시키고, 분광학적 분석 및 전기화학적 특성을 평가하여 SWCNT 전자 필름의 향상된 전기화학적 특성을 확인하였다. 전자 필름 상에 고분자 전해질 및 포도당 산화환원 효소를 layer-by-layer 기법으로 효율적으로 집적하여, 최종적으로 음전압 범위에서 구동이 가능한 포도당(glucose) 바이오센서를 구현하였다. 개발된 포도당 바이오센서는 효소와 SWCNT 전자 필름과의 높은 전하 전달 효율을 바탕으로 -0.45 vs. Ag/AgCl 음전압 범위에서 높은 산화환원 신호를 보였을 뿐 아니라 0~1 mM의 낮은 글루코스 농도 변화에서 약 98 ㎂/mM·cm²의 높은 감도를 보였다. 또한 음전압 구동을 통하여, 산화 반응을 일으킬 수 있는 4종의 방해물질(요산, 아스코르빅산, 도파민, 아세타아미노펜) 환경에서 4% 이하의 변화를 보여 높은 선택성을 보였다.

• Transactions on Electrical and Electronic Materials
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• 제9권2호
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• pp.52-56
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• 2008

Carbon nanotube films were fabricated by the catalytic CVD method. Plasma processed time effects on the field emission property were studied. The atomic structure was observed by using X-ray photoelectron spectroscopy (XPS). The surface composition changes were observed on the plasma processed CNT films. The O1s/C1s signal ratio and the Fls/Cls signal ratio changed from 1.1 % to 24.65 % and from 0 % to 3.1 % with plasma process time, respectively. We could guess it from these results that the Ar plasma process could change the surface composition effectively. In the case of the original-CNT film, no carbon shift was observed. In the case of the Ar plasma processed CNT films, however the oxygen related carbon shifts were observed. This oxygen related carbon shift at higher binding energy implies the increment of amount of the oxygen. It's possible that the increment of these bonds between carbon and oxygen results in the improvement of field emission performance.

• 한국항공우주학회지
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• 제40권11호
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• pp.1010-1015
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• 2012

본 연구에서 폐열 에너지를 수집하여 직접 전기로 변환하는 박막형 열전지를 제작하였다. 전도성 탄소섬유에 탄소나노튜브를 코팅함으로써 전기 전도도는 증가하였고, 다양한 곡률 반경에 대한 굽힘 실험에서 전극의 저항변화는 없었다. 열전지의 최대출력은 온도차의 제곱에 비례하여 증가하였으며, $3.4^{\circ}C$의 온도차에서 2.5 mW/kg의 전력을 생산하였다. 12시간의 방전 실험 결과, 열전지는 지속적으로 구동이 가능함을 확인하였다. 또한, 유연한 열전지를 뜨거운 유체가 흐르는 파이프에 감아 구동한 결과, 파이프의 곡률반경에 따라 내부저항은 감소하였고, 생산된 전력은 최대 30 % 상승하였다. 따라서 제작된 열전지는 다양한 곡면형 열원에 적용이 가능하다.

• Tribology and Lubricants
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• 제39권1호
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• pp.8-12
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• 2023

This study presents a molecular simulation of adhesion control between carbon nanotube (CNT) and Ag thin film deposited on silicon substrate. Rough and flat Ag thin film models were prepared to investigate the effect of surface roughness on adhesion force. Heat treatment was applied to the models to modify the adhesion characteristics of the Ag/CNT interface based on thermal wetting. Simulation results showed that the heat treatment altered the Ag thin film morphology by thermal wetting, causing an increase in contact area of Ag/CNT interface and the adhesion force for both the flat and rough models changed. Despite the increase in contact area, the adhesion force of flat Ag/CNT interface decreased after the heat treatment because of plastic deformation of the Ag thin film. The result suggests that internal stress of the CNT induced by the substrate deformation contributes in reduction of adhesion. Contrarily, heat treatment to the rough model increases adhesion force because of the expanded contact area. The contact area is speculated to be more influential to the adhesion force rather than the internal stress of the CNT on the rough Ag thin film, because the CNT on the rough model contains internal stress regardless of the heat treatment. Therefore, as demonstrated by simulation results, the heat treatment can prevent delamination or wear of CNT coating on a rough metallic substrate by thermal wetting phenomena.

• 센서학회지
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• 제18권2호
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• pp.168-172
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• 2009

In this paper, we present the carbon nanotube field-effect transistor(CNT-FET) with a double-gate structure. A Carbon nanotube film was aligned by the Langmuir-Blodgett technique and $SiN_x$ was deposited to protect from water, oxygen, and other contaminants. We measured the electrical characteristics of the proposed device as the function of the $V_{BG}$, $V_{TG}$. From this result, we can confirm that proposed device might be employed as a biosensor.

• 한국산학기술학회:학술대회논문집
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• 한국산학기술학회 2006년도 춘계학술발표논문집
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• pp.203-206
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• 2006

The sensor consists of a heater, an insulating layer, a pair of contact electrodes, and CNT-sensing film on a micromachined diaphragm. The heater plays a role in the temperature change to modify sensor operation. Gas sensor responses of CNT-film to $NO_2$ at room temperature are reported. The sensor exhibits a reversible response with a time constant of a few minutes at thermal treatment temperature of $130^{\circ}C$.

• 한국분말재료학회지
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• 제24권3호
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• pp.248-253
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• 2017

In this study, we investigate the effect of the diffusion barrier and substrate temperature on the length of carbon nanotubes. For synthesizing vertically aligned carbon nanotubes, thermal chemical vapor deposition is used and a substrate with a catalytic layer and a buffer layer is prepared using an e-beam evaporator. The length of the carbon nanotubes synthesized on the catalytic layer/diffusion barrier on the silicon substrate is longer than that without a diffusion barrier because the diffusion barrier prevents generation of silicon carbide from the diffusion of carbon atoms into the silicon substrate. The deposition temperature of the catalyst and alumina are varied from room temperature to $150^{\circ}C$, $200^{\circ}C$, and $250^{\circ}C$. On increasing the substrate temperature on depositing the buffer layer on the silicon substrate, shorter carbon nanotubes are obtained owing to the increased bonding force between the buffer layer and silicon substrate. The reason why different lengths of carbon nanotubes are obtained is that the higher bonding force between the buffer layer and the substrate layer prevents uniformity of catalytic islands for synthesizing carbon nanotubes.

• 산업기술연구
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• 제34권
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• pp.39-43
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• 2014

This paper represents a highly porous MWCNT film electrode with interconnected open pores and demonstrated the possibility of using an MWCNT network film as the top electrode for polyimide capacitive humidity sensors. Polyimide humidity sensors with MWCNT electrodes exhibited about 6 times faster response than equivalent Cr electrode sensors. This result may be due to their percolated pore structures, which make water molecules accessible to all polyimide surfaces. The much faster response times of MWCNT electrode sensors is attributed to the percolated pore network, which allows more water molecules to be accessible to polyimide surfaces.

• Bulletin of the Korean Chemical Society
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• 제31권8호
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• pp.2207-2210
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• 2010

This paper describes the preparation and study of thermally stimulated discharge conductivity (TSDC) study of cellulose triacetate (CTA) - multiwalled carbon nanotubes (MWNTs) film thermoelectrets. TSDC has been carried out in the temperature range 308 - 503 K and at four different polarizing fields. The conductivity of the polymer blends increased with increase in temperature showing a semi-conducting behavior. The apparent activation energy also showed a pronounced effect with the increase in the content of MWNTs.