• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.412-412
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• 2009

Carbon-based nano materials have a significant effect on various fields such as physics, chemistry and material science. Therefore carbon nano materials have been investigated by many scientists and engineers. Especially, since graphene, 2-dimemsonal carbon nanostructure, was experimentally discovered graphene has been tremendously attracted by both theoretical and experimental groups due to their extraordinary electrical, chemical and mechanical properties. Electrical conductivity of graphene is about ten times to that of silicon-based material and independent of temperature. At the same time silicon-based semiconductors encountered to limitation in size reduction, graphene is a strong candidate substituting for silicon-based semiconductor. But there are many limitations on fabricating large-scale graphene sheets (GS) without any defect and controlling chirality of edges. Many scientists applied micromechanical cleavage method from graphite and a SiC decomposition method to the fabrication of GS. However these methods are on the basic stage and have many drawbacks. Thereupon, our group fabricated GS through Thermo-electrical Pulse Induced Evaporation (TPIE) motivated by arc-discharge and field ion microscopy. This method is based on interaction of electrical pulse evaporation and thermal evaporation and is useful to produce not only graphene but also various carbon-based nanostructures with feeble pulse and at low temperature. On fabricating GS procedure, we could recognize distinguishable conditions (electrical pulse, temperature, etc.) to form a variety of carbon nanostructures. In this presentation, we will show the structural properties of OS by synthesized TPIE. Transmission Electron Microscopy (TEM) and Optical Microscopy (OM) observations were performed to view structural characteristics such as crystallinity. Moreover, we confirmed number of layers of GS by Atomic Force Microscopy (AFM) and Raman spectroscopy. Also, we used a probe station, in order to measure the electrical properties such as sheet resistance, resistivity, mobility of OS. We believe our method (TPIE) is a powerful bottom-up approach to synthesize and modify carbon-based nanostructures.

• 한국전기전자재료학회논문지
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• 제36권5호
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• pp.531-535
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• 2023

Mechanoluminescence (ML) is a phenomenon where the application of mechanical force to ML materials generates an electric field and produces light, holding significant promise as an eco-friendly technology. However, challenges in commercializing ML technology has arisen due to its low brightness and short luminous lifetime. To address this, in this work, we enhance ML efficiency by mixing carbon nanotubes (CNTs) into a ZnS: Cu embedded in a polydimethylsiloxane composite ML device. The inclusion of CNTs boosts ML intensity by 98% compared to devices without CNTs, as the increasing CNT fraction elevates conductivity, thereby amplifying ML intensity. However, this increase in CNT fraction also leads to enhanced light absorption within the device. Consequently, we observe a trend where ML intensity rises initially but declines beyond a CNT fraction of 0.0015 wt%. Based on these findings, we anticipate that our research will make valuable contributions to the advancement of electrical powerless mechanoluminescent technology.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권4호
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• pp.139-143
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• 2005

For application of carbon nano-tube (CNT) as a counter electrode materials of dye-sensitized solar cell (DSSC), the electrochemical behavior of CNT electrode was studied, employing cyclic-voltammetry (C-V) and impedance spectroscopy. Fabrication of CNT-paste and formation of CNT-counter electrode for characteristic measurement have been carried out using ball-milling and doctor blade process, respectively. Unit cell for measurements was assembled using Pt electrode, CNT electrode, and iodine-embedded electrolyte. Field emission-scanning electron microscopy (FE-SEM) was used for structural investigation of CNT powder and electrode. Sheet resistance of electrode was measured with 4-point probe method. Electrochemical properties of electrode, C-V and impedance spectrum, were studied, employing potentiogalvanostat (EG&G 273A) and lock in amplifier (EG&G 5210). As a results, the sheet resistance of CNT electrode is almost similar to that of F-doped SnO2 (FTO) coated glass substrate as approximately 10 ohm/sq. From C-V and impedance spectroscopy measurements, it was found that CNT electrode has high reaction rate and low interface reaction resistance between CNT surface and electrolyte. These results provides that CNT electrode were superior to that of conventional Pt electrode. Particularly, the reaction rate in the CNT electrode is about thrice high than Pt electrode. Therefore. CNT electrode is to be good candidate material for counter electrode in DSSC.

• Structural Engineering and Mechanics
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• 제69권4호
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• pp.439-455
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• 2019

This research deals with thermo-electro-mechanical buckling analysis of the sandwich nano-beams with face-sheets made of functionally graded carbon nano-tubes reinforcement composite (FG-CNTRC) based on the nonlocal strain gradient elasticity theory (NSGET) considering various higher-order shear deformation beam theories (HSDBT). The sandwich nano-beam with FG-CNTRC face-sheets is subjected to thermal and electrical loads while is resting on Pasternak's foundation. It is assumed that the material properties of the face-sheets change continuously along the thickness direction according to different patterns for CNTs distribution. In order to include coupling of strain and electrical field in equation of motion, the nonlocal non-classical nano-beam model contains piezoelectric effect. The governing equations of motion are derived using Hamilton principle based on HSDBTs and NSGET. The differential quadrature method (DQM) is used to calculate the mechanical buckling loads of sandwich nano-beam as well as critical voltage and temperature rising. After verification with validated reference, comprehensive numerical results are presented to investigate the influence of important parameters such as various HSDBTs, length scale parameter (strain gradient parameter), the nonlocal parameter, the CNTs volume fraction, Pasternak's foundation coefficients, various boundary conditions, the CNTs efficiency parameter and geometric dimensions on the buckling behaviors of FG sandwich nano-beam. The numerical results indicate that, the amounts of the mechanical critical load calculated by PSDBT and TSDBT approximately have same values as well as ESDBT and ASDBT. Also, it is worthy noted that buckling load calculated by aforementioned theories is nearly smaller than buckling load estimated by FSDBT. Also, similar aforementioned structure is used to building the nano/micro oscillators.

• 한국전기전자재료학회논문지
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• 제19권7호
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• pp.631-635
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• 2006

The properties of metal interlayered DLC films between the Si substrate and the DLC films were studied. DC magnetron sputtering method has been used to deposit intermediate layers of metals. And RF-PECVD method has been employed to synthesize DLC onto substrates of the silicon and metal layers. After we used metal Inter-layers, such as chromium, nickel, titanium and we studied tribological properties of the DLC films. The thickness of films were observed by field emission scanning electron microscope (FE-SEM). Also the surface morphology of the films were observed by an atomic force microscope (AFM). The crystallographic properties of the films were analyzed with X-ray diffraction (XRD), the friction coefficients were investigated by AFM in friction force microscope (FFM) mode. Tribological performances of the films were estimated by nano-indenter, stress tester measurement.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.421-421
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• 2009

Since carbon nanotubes (CNTs) are discovered, tremendous attentions have been paid to these materials due to their unique mechanical, electrical and chemical properties. Thereupon, many methods to produce a large scale of CNTs have been contrived by many scientists and engineers. Thus the examination of growth mechanisms of CNTs, which is essential to produce CNTs in large scale, has been an attractive issue. Though many scientists have been strived to investigate and understand the growth mechanisms of CNTs, many of them still remain controversial or unclear. Here we introduce representative growth mechanisms of CNTs, based on broadly employed fabrication methods of CNTs. We applied Thermo-electrical Pulse Induced Evaporation (TPIE) method based on field and thermal evaporation to synthesis of CNTs. However TPIE method was originally devised to fabricate graphene sheets and $Ge_2Sb_2Te_5$ nanostructures. While performing TPIE experiments to synthesize graphene, we eventually found experimental results widely supporting the growth model of CNTs proposed already. We observed the procedure of growth of CNTs obtained by TPIE method through Transmission Electron Microscopy (TEM). We believe this study provides an experimental basis on understanding and investigating carbon-based nanomaterials.

• Advances in nano research
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• 제6권4호
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• pp.299-321
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• 2018

A layerwise shear deformation theory is applied in this paper for buckling analysis of piezoelectric truncated conical shell. The core is a multiphase nanocomposite reinforced by carbon nanotubes (CNTs) and carbon fibers. The top and bottom face sheets are piezoelectric subjected to 3D electric field and external voltage. The Halpin-Tsai model is used for obtaining the effective moisture and temperature dependent material properties of the core. The proposed layerwise theory is based on Mindlin's first-order shear deformation theory in each layer and results for a laminated truncated conical shell with three layers considering the continuity boundary condition. Applying energy method, the coupled motion equations are derived and analyzed using differential quadrature method (DQM) for different boundary conditions. The influences of some parameters such as boundary conditions, CNTs weight percent, cone semi vertex angle, geometrical parameters, moisture and temperature changes and external voltage are investigated on the buckling load of the smart structure. The results show that enhancing the CNTs weight percent, the buckling load increases. Furthermore, increasing the moisture and temperature changes decreases the buckling load.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.567-567
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• 2012

Since the carbon nanotubes (CNTs) have extraordinary material properties, many researchers are trying to make a practical application in various fields [1]. In particular, the high surface area of CNTs was fascinated for nano-template on the catalytic system. $RuO_2$ coated CNTs are useful functional nano-composites in many applications, including super capacitors, fuel cells, biosensors, and field emitters. However, the research of interaction between CNTs and $RuO_2$ was not satisfied with various fields [2]. In this study, we will introduce the change of chemical and electrical state of $RuO_2$/CNTs at different temperatures by synchrotron radiation photoemission spectroscopy (SRPES). The t-MWCNTs used in this experiment were grown on the Ni/TiN/Si substrates by chemical vapor deposition. $RuO_2$ of 4-20 nm in thickness was deposited on the t-MWNTs by sputter. The SRPES measurements were carried out at the 4B1 beamline of the Pohang Accelerator Laboratory in Korea. The result of XPS measurement indicates that the deposited $RuO_2$ on the CNTs was reduced into pure Ru at above $300^{\circ}C$. And we confirmed that the effective work function of $RuO_2$/CNTs was decreased with increasing temperature.

• 한국생산제조학회지
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• 제26권2호
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• pp.172-184
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• 2017

Nanotechnology is a leading branch of technology and is expected to improve national industrial competitiveness. For maintaining a sustainable growth in nanotechnology, Korean government has set up specific plans from a long-term perspective. One of these plans is tracking and promoting certain potential technologies called Future 30 Nanotechnologies. This study aims to develop an analysis framework for comprehending the Future 30 Nanotechnologies. We applied this framework to the carbon nanomaterials field. Through co-authorship and keyword network analysis, we identified the research trends of three countries (i.e., Korea, US, and China.). This research framework could be utilized in the development of a nanotechnology policy.

• 공업화학
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• 제27권5호
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• pp.502-507
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• 2016

본 연구에서는 탄소나노튜브, 니켈 및 산화아연의 항균특성 활용을 목적으로 새로운 항균 나노 복합 재료를 개발하였다. 니켈 코팅된 탄소나노튜브의 제조 및 그들의 동시발생 집중 및 비활성 세균에 대한 항균소재의 잠재적 응용성을 평가하였다. 제조된 니켈 도금 탄소나노튜브의 형상 및 니켈 도금은 전계 방출 주사전자현미경(FE-SEM) 및 X선 에너지 분산 분광기(EDS)를 사용하여 분석하였다. 나노복합소재의 항균 특성을 확인할 수 있는 타깃 세균은 황색포도상구균과 대장균으로 지정하였다. 니켈 도금된 탄소나노튜브와 산 처리된 탄소나노튜브로 각각 강화된 나노복합소재의 황색포도상구균 및 대장균에 대한 항균특성을 비교하였을 때, 니켈 도금된 탄소나노튜브/산화아연으로 강화된 나노복합소재의 항균 특성이 더 우수한 결과를 보이는 것을 확인할 수 있었다. 이러한 결과에 따라서, 탄소나노튜브 표면에 도금된 니켈이 복합소재 내에서 세균의 살균 작용에 중요한 역할을 하는 것으로 판단할 수 있다. 또한, 첨가된 산화아연은 나노복합소재의 항균특성 향상을 목적으로 제안되었다.