• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.935-938
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• 2001

Carbon nanotubes(CNTs) was successfully grown on Ni coated silicon wafer substrate by applying PECVD technique(Plasma Enhanced Chemical Vapor Deposition). As a catalyst, Ni thin film of thickness ranging from 15∼30nm was prepared by electron beam evaporator method. In order to find the optimum growth condition, the type of the gas mixture such as C$_2$H$_2$-NH$_3$was systematically investigated by adjusting the gas mixing ratio in temperature of 600$^{\circ}C$ under the pressure of 0.4 torr. The diameter of the grown CNTs was 40∼150nm. As NH$_3$etching time increased the diameters of the nanotubes decreased whereas the density of nanotubes increased. TEM images clearly demonstrated synthesized nanotubes was multiwalled. We investigated electrical properties for the application of FED.

• 한국전기전자재료학회논문지
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• 제14권9호
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• pp.751-756
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• 2001

Carbon nanotubes(CNTs) was successfully grown on Ni coated silicon wafer substrate by PECVD technique(Plasma Enhanced Chemical Vapor Deposition). As a catalyst, Ni thin film of thickness ranging from 15∼30nm was prepared by electron beam evaporator system. In order to find the find the optimum growth condition, initially two different types of gas mixtures such as C$_2$H$_2$-NH$_3$ and C$_2$H$_2$-NH$_3$-Ar were systematically investigated by adjusting the gas mixing ratio in temperature of 600$^{\circ}C$ under 0.4 torr. The diameter of the grown CNTs was 40∼200nm. The diameter of the CNTs increases with increasing the Ni particles size. TEM images clearly demonstrated synthesized nanotubes to be multiwalled.

• 센서학회지
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• 제30권4호
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• pp.255-260
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• 2021

We studied electrochemical sensors using printed carbon nanotube (CNT) film on a polyethylene terephthalate (PET) substrate. Multiwalled CNT films were printed on a PET substrate to study its feasibility as hazardous and noxious substances (HNS) detection sensor. The printed CNT film (PCF) with a 50 ㎛ thickness exhibited a specific resistance of 230 ohm. To determine the optimum sensor structure, a resistance-type PCF sensor (R-type PCF sensor) and a conductive-type PCF sensor (C-type PCF sensor) were fabricated and compared using diluted NH₃ droplets with various concentrations. The response magnitude, response time, sensitivity, linearity, and limit of detection (LOD) were compared, and it was concluded that the C-type PCF sensor exhibited superior performance. By applying a C-Type PCF sensor, we confirmed the detection performance of 12 types of floating HNS and the response of the sensor with selectivity according to the degree of polarity.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1536-1537
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• 2005

We have made point electron sources using carbon nanotubes (CNTs). For the fabrication of point electron sources, CNTs were dispersed in a solution and attached on electrochemically etched W tips using electrophoresis. In our study, we have utilized various CNTs such as single-walled CNT (SWCNT), multiwalled CNT (MWCNT), and thin-MWCNT and threshold current, turn-on voltage, filed enhancement factor of each emitter have been studied upon a tube/bundle diameter and length. In addition, fieldemitted electron energy distribution of various CNT emitters is characterized.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 C
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• pp.1628-1630
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• 2000

Vertically aligned multiwalled carbon nanotubes are grown on silicon oxide substrate at 950$^{\circ}C$ by thermal chemical vapor deposition using $C_{2}H_2$. Three catalytic metals such as iron(Fe), cobalt (Co), and nickel(Ni) are used as catalyst, we found that the growth rate of carbon nanotubes for three catalyst particles are in an order of Fe > Ni > Co. All carbon nanotubes are revealed to have bamboo structure with no encapsulated catalytic particles, the diameter of carbon nanotubes depend on the catalyst, the tip and the compartment sheets of bamboo structure also depend on the shape of catalytic particles.

• 한국전기전자재료학회논문지
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• 제26권4호
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• pp.315-320
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• 2013

The composites composed of conducting polymer (MEH-PPV), CdTe nanoparticles, and multiwalled carbon nanotubes (MWNTs) were spectroscopically and electrically characterized in their thin films. The composite films were prepared by spray coating. These composites were prepared from the mixture solution of MEH-PPV and CdTe-embedded MWNTs, in which CdTe nanoparticles were electrostatically bound to MWNTs. UV/vis and PL spectra were analyzed to investigate the optical absorbance and emission of the composite films. In addition, their structural, electrochemical, and electrical properties were studied by transmission electron microscopy, cyclic voltammetry, and I-V measurement.

• Composites Research
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• 제32권6호
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• pp.375-381
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• 2019

Multiwalled carbon nanotubes (MWCNTs) are covalently functionalized with isocyanates by directly reacting commercial hydroxyl functionalized MWCNTs with excess 4,4'-methylenebis (phenyl isocyanate) (MDI) and hexamethylene diiosocyanate (HDI). HDI-modified MWCNTs results in a higher surface isocyanate density than MDI-modified MWCNTs. Anionic ring-opening polymerization of ε-caprolactam is conducted using a sodium caprolactam initiator in combination with a di-functional hexamethylene-1,6-dicarbamoylcaprolactam activator in the presence of isocyanate functionalized MWCNTs. This polymerization proceeds in a highly efficient manner at relatively low reaction temperature (150℃) and short reaction times (10 min). During the polymerization, the isocyanate functionalized MWCNTs act not only as reinforcing fillers but also as second activators. Nanocomposites with HDI modified MWCNTs exhibit higher reinforcement and faster isothermal crystallization than MDI modified MWCNTs. The results show that PA6 chains grow more effectively from HDI modified MWCNT surface than from MDI modified MWCNT surface, resulting in stronger interaction between PA6 and MWCNTs.

• 한국전기전자재료학회논문지
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• 제15권4호
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• pp.367-372
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• 2002

The vertically well-aligned carbon nanotubes(CNTs) were successfully grown on Ni coated silicon wafer substrate by DC bias-assisted PECVD(Plasma Enhanced Chemical Vapor Deposition). As a catalyst, Ni thin film of thickness ranging from 15~30nm was prepared by electron beam evaporator method. In order to find the optimum growth condition, the type of gas mixture such as $C_2H_2-NH_3$ was systematically investigated by adjusting the gas mixing ratio at $570^{\circ}C$ under 0.4Torr. The diameter of the grown CNTs was 40~200nm and the diameter of the CNTs increased with increasing the Ni particles size. TEM images clearly showed carbon nanotubes to be multiwalled. The measured turn-on field was $3.9V/\mu\textrm{m}$ and an emission current of $1.4{\times}10^4A/\textrm{cm}^2$ was $7V/\mu\textrm{m}$. The CNTs grown by bias-assisted PECVD was able to demonstrate high quality in terms of vertical alignment, crystallization of graphite and the processing technique at low temperature of $570^{\circ}C$ and this can be applied for the emitter tip of FEDs.

• Steel and Composite Structures
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• 제26권5호
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• pp.649-662
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• 2018

In this study, based on the three-dimensional theory of elasticity, free vibration characteristics of sandwich sectorial plates with multiwalled carbon nanotube-(MWCNT)-reinforced composite core are considered. Modified Halpin-Tsai equation is used to evaluate the Young's modulus of the MWCNT/epoxy composite samples by the incorporation of an orientation as well as an exponential shape factor in the equation. The exponential shape factor modifies the Halpin-Tsai equation from expressing a straight line to a nonlinear one in the MWCNTs wt% range considered. In this paper, free vibration of thick functionally graded sandwich annular sectorial plates with simply supported radial edges and different circular edge conditions including simply supported-clamped, clamped-clamped, and free-clamped is investigated. A semi-analytical approach composed of two-dimensional differential quadrature method and series solution are adopted to solve the equations of motion. The material properties change continuously through the core thickness of the plate, which can vary according to a power-law, exponentially, or any other formulations in this direction. This study serves as a benchmark for assessing the validity of numerical methods or two-dimensional theories used to analysis of laminated sectorial plates.

• 분석과학
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• 제23권2호
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• pp.165-171
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• 2010

글루코스 옥시다아(GOx)제 고정화 바이오센서를 두 가지 방법으로 제조 하였다. 첫 번째 방법은 폴리(maleic anhydride) 그래프트 탄소나노튜브(PMAn-g-MWCNT) 전극에 감마선 조사법으로 제조 된 Au 나노입자를 물리적으로 흡착시킨 후, GOx을 고정화 시켜 바이오센서를 제조한 경우이고, 다른 하나는 PMAn-g-MWCNT 전극에서 Au 이온을 전기화학적으로 환원시켜 Au 나노입자를 코팅 시키고, 그 위에 GOx을 고정화 시켜 바이오센서를 제조 한 경우이두. 제조된 바이오센서에 대해 효율 평가를 수행 하였는데, 물리적 흡착법으로 제조된 전극의 경우 검출 범위는 $30\;{\mu}M\sim100\;{\mu}M$이었으며, 검출한계는 $15\;{\mu}M$이었다. 또한 ascorbic acid와 uric acid에 대한 검출한계는 7.6%이었다. 물리적으로 Au 나노입자가 흡착된 전극의 경우가 글루코스 측정에 매우 우수한 전극임을 확인 하였다.