• 한국표면공학회지
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• 제33권2호
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• pp.69-76
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• 2000

The rf plasma chemical vapor deposition is a common method employed for diamond or amorphous carbon deposition. Diamond possesses the strongest bonding, as exemplified by a number of unique properties-extraordinary hardness, high thermal conductivity, and a high melting tempera tore. Therefore, it is very important to investigate the synthesis of semiconducting diamond and its use as semiconductor devices. An inductively coupled rf plasma CVD system for producing amorphous carbon films were developed. Uniform temperature and concentration profiles are requisites for the deposition of high quality large-area films. The system consists of rf matching network, deposition chamber, pumping lines for gas system. Gas mixtures with methane, and hydrogen have been used and Si (100) wafers used as a substrate. Amorphous carbon films were deposited with methane concentration of 1.5% at the process pressure of S torr~20 torr, and process temperature of about $750^{\circ}C$. The nucleation and growth of the amorphous carbon films have been characterized by several methods such as SEM and XRD.

• 대한기계학회논문집B
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• 제30권1호
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• pp.82-86
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• 2006

Carbon nanotubes have attracted much attention as future mechanical and electronic materials. However, manipulating techniques are not well developed yet. Here we propose to use electrostatic drop-on-demand devices to eject micro-droplets containing micelle-suspended single-walled carbon nanotubes. A simple electrostatic force analysis and photographic studies of droplet ejection process are presented. The analytical analysis shows that semiconducting species have higher electrostatic force density. However, enrichment of specific electronic types is not clear at large size droplets produced in this study. A micro-scale jetting device is being produced to prove the suggested behavior.

• 한국진공학회지
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• 제20권4호
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• pp.294-299
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• 2011

본 연구에서는 열화학기상증착법과 나노구조의 Fe/$Al_2O_3$/Si 촉매층을 이용하여 단일벽 탄소나노튜브를 합성하고 마이크로웨이브 조사를 통해 금속성 단일벽 탄소나노튜브를 선택적으로 제거하고 반도체성 단일벽 탄소나노튜브를 분리하였다. 조사시간의 변화에 따른 단일벽 탄소나노튜브의 전기적, 구조적 특성을 분석한 결과, 조사시간이 120초인 경우, 금속성의 단일벽 탄소나노튜브가 선택적으로 제거되어 약 95%의 반도체성 단일벽 탄소나노튜브를 분리할 수 있었으며, 뿐만 아니라 남아있는 반도체성 단일벽 탄소나노튜브가 손상 없이 우수한 결정성을 지니는 것을 확인할 수 있었다. 이러한 방법은 반도체성 단일벽 탄소 나노튜브를 기반으로 한 전계효과 트랜지스터 및 다양한 나노전자소자의 응용에 유용한 정보를 제공하리라 기대한다.

• Carbon letters
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• 제27권
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• pp.35-41
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• 2018

Surfactant-wrapped separation methods of metallic and semiconducting single-walled carbon nanotubes (SWCNTs) can result in large changes in intrinsic physical and chemical properties due to electronic interactions between a nanotube and a surfactant. Our approach to synthesize SWCNTs with an electronic feature relied on utilizing carbon nanorings, [n] cycloparaphenylenes ([n]CPPs), which are the fundamental unit of armchair type SWCNTs (a-SWCNTs) that possess a metallic feature without any surfactants. To obtain long tubular structures from [n]CPPs, the host-guest complexes formed with well-aligned [n]CPP hosts and various fullerene guests on a silicon substrate were pyrolyzed under an ethanol gas flow at a high temperature with focused-ultraviolet laser irradiation. The pyrolyzed [n]CPPs were observed to transform from nanorings to tubular structures with 1.5-1.7 nm diameters corresponding to the employed diameter of [n]CPPs. Our approach suggests that [n]CPPs are useful for structure-controlled synthesis of SWCNTs.

• KIEE International Transactions on Electrophysics and Applications
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• 제4C권1호
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• pp.1-4
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• 2004

This paper presents an investigation of the phase-resolved partial discharge (PD) pattern of PET (Poly Ethylene Telephthalate) films with carbon black particles. The phase-resolved PD pattern and statistical parameter from PET samples according to the number of included semiconductor particles were measured. The measurement system consisted of a conventional PD detector using a digital signal processing technique. The partial discharge patterns of the PET films that include the semiconductor particles were investigated to simulate an actual situation that may exist in the cable. In addition, difference of PD patterns between semiconducting particles in PET films and artificial voids was studied. The relationship between the numbers of semiconductor particles in PET films was discussed through the difference of Ψ-q-n distribution and statistical analysis.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.179.2-179.2
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• 2014

Carbon nanotubes (CNT)-metal contacts play an important role in nanoelectronics applications such as field-effect transistor (FET) devices. Using Al and (10,0) CNT, we have recently showed that the CNT-metal contacts mediated via topological defects within CNT exhibits intrinsically low contact resistance, thanks to the preservation of the sp2 bonding network at the metal-CNT contacts.[1] It is well-established that metals with good wetting property such as Pd consistently yield good contacts to both metallic and semiconducting CNTs. In this work, the electronic and charge transport properties of the interfaces between capped CNT and Pd will be investigated based on first-principles computations and compared with previous results obtained for the Al electrodes.

• 한국광학회:학술대회논문집
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• 한국광학회 2008년도 하계학술발표회 논문집
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• pp.289-290
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• 2008

• Carbon letters
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• 제10권1호
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• pp.9-13
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• 2009

We propose an evaluation method of the relative content of single-walled carbon nanotubes (SWCNT) in SWCNT soot synthesized by arc discharge using UV-VIS-NIR absorption spectroscopy. In this method, we consider the absorbance of semiconducting and metallic SWCNTs together to calculate the relative content of SWCNTs with respect to a highly purified reference. Our method provides the more reliable and realistic evaluation of SWCNT content with respect to the whole carbonaceous content than the previously reported method.

• Carbon letters
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• 제15권2호
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• pp.77-88
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• 2014

Double walled carbon nanotubes (DWCNTs) are considered an ideal model for studying the coupling interactions between different concentric shells in multi-walled CNTs. Due to their intrinsic coaxial structures they are mechanically, thermally, and structurally more stable than single walled CNTs. Geometrically, owing to the buffer-like function of the outer tubes in DWCNTs, the inner tubes exhibit exciting transport and optical properties that lend them promise in the fabrication of field-effect transistors, stable field emitters, and lithium ion batteries. In addition, by utilizing the outer tube chemistry, DWCNTs can be useful for anchoring semiconducting quantum dots and also as effective multifunctional fillers in producing tough, conductive transparent polymer films. The inner tubes meanwhile preserve their excitonic transitions. This article reviews the synthesis of DWCNTs, their electronic structure, transport, and mechanical properties, and their potential uses.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.58-58
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• 2010

Carbon nanotubes (CNTs) have been extensively studied owing to its superior electrical properties, especially high electron mobility, which can be applied to various nano-electronic devices. However, synthesized CNTs have a mixture of metallic and semiconducting tubes so that their separation has been a tremendous obstacle to the practical application in electronic device structures. Among the different separation methods, electrical breakdown process to selectively burn out the metallic tubes has been quite successful though it needs additional process in the fabrication of device structures. Here, we report on the selective but not perfect growth of semiconducting nanotubes via use of diluted ferritin catalyst. SWCNTs were grown on ferritin catalyst, where the concentration of the ferritin solution was changed. In this way, we could fabricate the electrical breakdown free SWCNT thin film transistors on the flexible polyimide (PI) substrate. When we used the ferritin diluted by 1/2000, ~ 60 % of the SWCNT thin film transistors showed a perfect p-type behavior with an on/off current ratio higher than $10^5$ and on-current greater than $10^{-7}$ A. We will also discuss the photo-response of such formed thin film transistors over both visible and UV light.