• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.3
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• pp.275-283
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• 2007

An experimental study was conducted to investigate the effect of the morphology of CNT (Carbon Nanotube) on the thermal conductivity of suspensions. The effective thermal conductivities of the samples were measured using a steady-state cut bar apparatus method. Enhancements based on the thermal conductivity of the base fluid are presented as functions of both the volume fraction and the temperature. Although functionalized SWNT (Single-Walled Carbon Nanotube) produced more stable and homogeneous suspensions, the addition of small amounts of surfactant to suspensions of 'as produced' SWNT demonstrated a greater increase in effective thermal conductivity than functionalized SWNT alone. The effective thermal conductivity enhancement corresponding to 1.0% by volume approached 10%, which was observed to be lower than expected, but more than twice the values, 3.5%, obtained for similar tests conducted using aluminum oxide suspensions. However, for suspensions of MWNT (Multi-Walled Carbon Nanotube), the degree of enhancement was measured to be approximately 37%. It was postulated that the effect of clustering, resulting from the multiple heat-flow passages constituted by interconnecting neighboring CNT clusters, played an important role in significant enhancement of effective thermal conductivity.

• Journal of Sensor Science and Technology
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• v.30 no.4
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• pp.229-235
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• 2021

This study presents a simple approach for the assembly of a free-standing conductive electronic nanofilm of single-walled carbon nanotubes (SWNTs) suitable for enzymatic electrochemical biosensors. A large-scale SWNT electronic film was successfully produced by the dialysis of p-Terphenyl-4,4''-dithiol (TPDT)-treated SWNTs. Furthermore, Horseradish peroxidase (HRP) was immobilized on the TPDT-SWNT electronic film, and the enzymatic detection of hydrogen peroxide (H₂O₂) was demonstrated without mediators. The detection of H₂O₂ in the negative potential range (-0.4 V vs. Ag/AgCl) was achieved by direct electron transfer of heme-based enzymes that were immobilized on the TPDT-SWNT electronic film. The SWNT-based biosensor exhibited a wide detection range of H₂O₂ from 10 µM to 10 mM. The HRP-doped SWNT electronic film achieved a high sensitivity of 342 ㎛A/mM·cm² and excellent selectivity against a variety of redox-active interfering substances, such as ascorbic acid, uric acid, and acetaminophen.

• Journal of Sensor Science and Technology
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• v.19 no.2
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• pp.160-167
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• 2010

In this paper, we fabricated the optoelectronic device based on Cadmium selenide(CdSe) nanocrystal quantum dots (NQDs)/single-walled carbon nanotubes(SWNTs) heterostructure using dieletrophoretic force. The efficient charge transfer phenomena from CdSe to SWNT make CdSe-Pyridine(py)-SWNT unique heterostructures for novel optoelectronic device. The conductivity of CdSe-py-SWNT was increased when it was exposed at ultra violet(UV) lamp, and varied as a function of wavelength of incident light.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.668-671
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• 2005

Carbon nanotubes exhibit strong fluorescence emissions in the region of near infrared regions where most biomolecules are transparent. Such signals are highly sensitive to environment variations as well as adsorption of specific biomolecules. In this research, single walled carbon nanotubes(SWNTs) are assembled with different types of DNAs and used to target specific types of DNAs. Dot blot investigations and corresponding raman spectroscopy observations demonstrated excellent selectivity of carbon nanotube-DNA bioconjugates. The results show possibility of using SWNT as generic nano-bio markers for precise detection of different kinds of genes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.122-123
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• 2005

단층벽 탄소나노튜브(Single-walled carbon nanotube)를 성장시키고 성장된 탄소나노튜브를 여러 단계의 여과과정이 필요 없는 단순한 정제과정을 통하여 비정질 탄소 찌꺼기, 촉매 금속 등의 불순물을 제거하였다. 성장 온도가 증가함에 따라 수율이 증가하고 불순물의 함유량이 적은 탄소나노튜브가 성장이 되었으며 전반적으로 0.41-2.0 nm의 균일한 직경을 가진 SWNT가 합성이 되었으며 정제 후 96% 이상의 순도를 가진 SWNT를 얻을 수 있었다. 전반적으로 실험결과에 대한 물질의 특성 은 field emission scanning electron microscopy (FESEM)와 X-ray diffraction (XRD) 그리고 Raman spectroscopy로 조사하였다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.881-885
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• 2004

We report a method for making a device on which semi-conducting single-walled carbon nanotubes are attached selectively between two metal electrodes. This method is divided two processes. First we can connect a rope of single-walled carbon nanotubes(SWNTs) between two electrodes using the electric field. But a SWNTs' rope obtained by the first process was composed of a few of metallic and semi-conducting SWNTs together. The second process is to burn the metallic and semi-conducting nanotubes through applying a voltage. As a result, we can obtain a semi-conducting SWNT device. To make the patterned electrodes, we deposited $SiO_2$(150nm) on a wafer. After then, we made a patterned samples with Ti(200 $\AA$)/Au(300$\AA$). We empirically obtained a electric condition 0.66 $V_{pp}$ /${\mu}{\textrm}{m}$@5MHz. From this result, we verified that most of current go through the metallic nanotubes in this device. When we apply DC voltage between two electrodes, the metallic carbon nanotubes are burnt. Finally, we can obtain a semi-conducting nanotube device which we desire to make. We got the I-V characteristic graph which has shown the semi-conducting property. We hope to apply to the various applications using this selective semi-conducting carbon nanotube deposition method.ethod.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.11
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• pp.1006-1011
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• 2004

Carbon nanotubes have outstanding properties which make them useful for a number of high-technology applications. Especially, single-walled carbon nanotube (SWNT), working under physical conditions (in aqueous solution) and converting electrical energy into mechanical energy directly, can be a good substitute for artificial muscle. The carbon nanotube structure simulated in this paper is an isotropic cantilever type with an adhesive tape which is sandwiched between two SWNTs. For predicting the geometrical and physical parameters such as deflection, slope, bending moment and induced force with various applied voltages, the analytical model for a 3 layer bimorph nanotube actuator is developed by applying Euler-Bernoulli beam theory. The governing equation and boundary conditions are derived from energy Principles. Also, the brief history of carbon nonotube is overviewed and its properties are compared with other functional materials. Moreover, an electro-mechanical coupling coefficient of the carbon nanotube actuator is discussed to identify the electro-mechanical energy efficiency.

• Transactions on Electrical and Electronic Materials
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• v.9 no.4
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• pp.169-172
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• 2008

We attempted to fabricate carbon nanotube field effect transistor (CNT-FET) using single walled carbon nanotube(SWNT) on the heavily doped Si substrate used as a bottom gate, source and drain electrode were fabricated bye-beam lithography on the 500 nm thick $SiO_2$ gate dielectric layer. We investigated electrical and physical properties of this CNT-FET using Scanning Probe Microscope(SPM) and conventional method based on tungsten probe tip technique. The gate length of CNT-FET was 600 nm and the diameter of identified SWNT was about 4 nm. We could observed gating effect and typical p-MOS property from the obtained $V_G-I_{DS}$ curve. The threshold voltage of CNT-FET is about -4.6V and transconductance is 47 nS. In the physical aspect, we could identified SWNT with phase mode of SPM which detecting phase shift by force gradient between cantilever tip and sample surface.

• International Journal of Precision Engineering and Manufacturing
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• v.9 no.3
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• pp.79-81
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• 2008

A single-wall carbon nanotube (SWNT) transparent conductive film (TCF) was fabricated using a simple inkjet printing method. The TCF could be selectively patterned by controlling the dot size to diameters as small as $34{\mu}m$. In this repeatable and scalable process, we achieved 71% film transmittance and a resistance of 900 ohm/sq sheet with an excellent uniformity, about ${\pm}5%$ deviation overall. Inkjet printing of SWNT is substrate friendly and the TCF is printed on a flexible substrate. This method of fabrication using direct printing permits mass production of TCF in a large area process, reducing processing steps and yielding low-cost TCF fabrications on a designated area using simple printing.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.103-105
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• 2009

본 연구에서 우리는 single walled carbon nanotube(SWNT) 용액 속의 TEOS와 VTMS 바인더가 나노튜브 센서의 감도의 증가와 선택성을 가지는 것에 대해서 조사하였다. 일반적으로 혼합된 SWNT 용액 속의 유기 화합물인 바인더는 기판에 잘 부착된다. 그리고 가수분해 된 바인더의 표면에는 바인더가 경화 되었을 때 기능화 된 하나의 그룹이 형성된다. 그것은 SWNT의 표면에 가수분해 된 TEOS와 VTMS의 -OH와 $-CH=CH_2$ 같이 기능화된 그룹이다. 그러므로 전하는 carbon nanotube와 흡착된 분자 사이에서 이동되고 그에 대한 영향으로 전기적인 전도성이 변화한다. 이 실험에서 증가되어지는 알콜 농도에 따라 TEOS 바인더를 사용한 센서의 저항은 감소하는 반면 VTMS 바인더를 사용한 센서의 저항은 증가한다.