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수직 가열로를 이용한 고순도 단일벽 탄소나노튜브 섬유의 합성
김태민,송우석,김유석,김수연,최원철,박종윤,Kim, Tae-Min,Song, Woo-Seok,Kim, Yoo-Seok,Kim, Soo-Youn,Choi, Won-Chel,Park, Chong-Yun 한국진공학회 2010 Applied Science and Convergence Technology Vol.19 No.5
Many routes have been developed for the synthesis of signle-walled carbon nanotubes (SWCNTs). We spun fibers of SWCNTs directly from vertical furnace using a liquid source of carbon and an iron-contained molecule. The solution was prepared by ethanol as a carbon source, in which ferrocene as a catalyst, thiophene were dissolved. It was then injected from the top of the furnace into hot zone with hydrogen as a carrier gas. We successfully synthesized high-quality SWCNTs by adjusting the various experimental conditions, such as concentration of ferrocene, solution injection rate, concentration of thiophene, and hydrogen flow rate. Measurement of Raman spectroscopy, scanning electron microscopy, and transmission electron microscopy were carried out to find the optimized conditions. The synthesized SWCNTs (1.16~1.64 nm) appeared a bundle structure and well-aligned parallel to the direction of furnace. These results also provide an simple way for high-quality SWCNTs mass production and fabricating direct spining SWCNTs fiber. It will allow one-step production of SWCNTs fiber with potentially excellent properties and wide-range applications.
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전기방사법을 이용한 고분자 나노섬유의 합성과 다중벽 탄소나노튜브의 혼합을 통한 물리적 강도 향상
이미현,송우석,김유석,장성원,최원철,박종윤,Lee, Mi-Hyun,Song, Woo-Seok,Kim, Yoo-Seok,Jang, Sung-Won,Choi, Won-Chel,Park, Chong-Yun 한국진공학회 2012 Applied Science and Convergence Technology Vol.21 No.1
Multi-walled carbon nanotubes (MWCNTs) incorporated polyacrylonitrile (PAN) and poly (methyl methacrylate) (PMMA) nanofibers were synthesized using electronspinning method. Effects of polymer concentration and applied voltage on the synthesis of PAN and PMMA nanofibers were systematically investigated. The structural characterization of PAN/MWCNTs and PMMA/MWCNTs composited nanofibers synthesized as a function of the MWCNTs concentration was performed by scanning electron microscopy and transmission electron microscopy. 5 wt% MWCNTs incorporated PAN and PMMA electrospun nanofiber exhibit best strength and stiffness.
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Europium 실리케이트의 열처리 조건에 따른 특성 변화
김은홍 ( Eun Hong Kim ),신영철 ( Young Chul Shin ),최원철 ( Won Chel Choi ),김범준 ( Bum Jun Kim ),김민호 ( Min Ho Kim ),김태근 ( Tae Geun Kim ) 한국전기전자재료학회 2006 한국전기전자재료학회 하계학술대회 논문집 Vol.2006 No.1
We investigate the influence of the ambient gas during thermal annealing on the photoluminescence (PL) properties of europium-silicate thin films. The films were fabricated on substrates by using a radio-frequency magnetron sputtering method and subsequent rapid thermal annealing (RTA). The mechanism for the formation of the europium silicates during the annealing process was investigated by using X-ray diffraction (XRD) spectroscopy, Auger electron spectroscopy (AES) and transmission electron microscopy (TEM). A series of narrow PL spectra from Eu3+ ions was observed from the film annealed in O2 ambient. Broad PL spectra associated with Eu2+ ions, with a maximum intensity at 600 nm and a FWHM of 110 nm, were observed from the thin film annealed at 1000℃ in N₂ ambient.
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이승엽(Seung Youb Lee),류동현(Dong Heon Ryu),홍준용,염민형(Min Hyeng Yeom),양지훈(Ji Hoon Yang),최원철(Won Chel Choi),권명회(Myeng Hoi Kwon),박종윤(Chong-Yun Park) 한국진공학회(ASCT) 2007 Applied Science and Convergence Technology Vol.16 No.4
본 연구에서는 Ag-Cu합금 코팅에 의한 탄소나노튜브의 전계방출특성 변화를 연구하였다. 화학기상증착 방법을 사용하여 수직 성장시킨 탄소나노튜브에 직류 마그네트론 스퍼터를 이용하여 Ag-Cu합금을 증착하였고, 열처리 전·후의 탄소나노튜브의 표면형상 변화와 전계방출특성에 변화를 연구하였다. 연구결과 Ag-Cu합금 코팅으로 전계방출 문턱전압이 현저히 낮아졌으며 전류밀도는 6 V/㎛의 인가전압 하에서 약 5배 향상된 것을 확인하였다. 또한 Ag-Cu합금이 코팅된 탄소나노튜브는 산소가 많이 포함된 분위기에서도 안정적인 전계방출 특성을 보였으며, 이는 Ag-Cu합금 코팅이 분위기 진공에 상존하는 산소기체가 탄소나노튜브를 공격하는 것을 막아주는 역할을 하여 열악한 분위기에서도 전계방출이 안정적으로 발생하였기 때문인 것으로 생각된다. The field emission properties of CNT-emitters coated with Ag-Cu alloy have been investigated. The vertical aligned multi-walled CNTs were synthesized by dc-plasma enhanced chemical vapor deposition (dc-PECVD) and the Ag-Cu alloy was coated by using dcmagnetron sputter. The morphology of alloy-coated and un-coated CNT-emitters was observed by using SEM and their field emission properties were also measured. Annealing the AgCu-coated CNTs at temperature more than ~700℃, the Ag-Cu alloy was diffused to and aggregated on the top of the CNT as a Q-tip. A significant progress on the field emission was not observed with coating Ag-Cu alloy on the CNTs, but a certain improvement in a resistance against oxygen gas was made confirmation. It seems to be due to inertness of Ag-Cu alloy on the CNTs.
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