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제108회 대한화학회 학술발표회, 총회 및 기기전시회 안내 The formation of geometrically controlled carbon coils by controlling SF6 amount

2011년 8월 1일 16시 15분 29초
Ⅱ-MAT.P-308 이곳을 클릭하시면 발표코드에 대한 설명을 보실 수 있습니다.
목 <발표Ⅱ>
저자 및
전영철, 김성훈1
신라대학교 에너지응용화학과, Korea
1신라대학교 신소재화학과, Korea
Due to their unique geometry and the chirality, carbon coils have been attracted as high potential materials for the electromagnetic wave absorbers with low reflection coefficient [1]. For the practical application of carbon coils, the mass production of carbon coils having the controlled-characteristics for the coil morphology and geometry (diameter, pitch, length, and turning direction) were needed. To do this, various kinds of the additives incorporation techniques have been widely investigated. Among the additives currently used in the formation of carbon coils, a trace of the sulfur-incorporated species was regarded as the promising promoter for the formation of carbon coils. Carbon coils were reported to be well-synthesized by adding just a trace of hydrogen sulfide (H2S) [2], carbon disulfide (CS2) [3], thiophene (C4H4S) as an impurity [4], or using WS2 as a catalytic material [5]. Different sulfur content on the catalyst surface was known to affect the catalytic activity [6, 7]. Despite the abundant reports for the sulfur-incorporated species addition in the formation of carbon coils, however, the detailed study on the effect of the sulfur-incorporated additives on the controlled geometrical characteristics of carbon coils as functions of the amounts and the injection times of the additive gases are few up to date. This work presents the enhancement of carbon coils production yield using SF6, as an additive gas, incorporation in the source gases. SF6 was known as an effective gas for the formation of micro-needles on the silicon surface via SF6/CF4 plasmas in the two-stage cyclic etching/deposition process [8]. It was also known that fluorine species in the precursor gas could decrease the deposition temperature and eventually increase the formation density of the diamond nuclei [9]. The addition of fluorine species was known to enhance the rate of hydrogen abstraction, thereby opening more nucleation sites for possible interaction with growth species even in the low temperature case [9]. In this work, we added SF6 in the source gases to take the advantage for the fluorine species role regarding the enhancement of the nucleation sites of carbon coils. We also manipulated SF6 incorporation time to obtain the controlled geometrical characteristics of carbon coils. According to the different reaction processes, the injection time and the amount of SF6 flow was varied. The characteristics of the as-grown carbon coils, namely the formation density and the geometry were examined and discussed. The sulfur role for the formation of carbon coils and the enhanced etching ability by the fluorine-related species were discussed. References [1] Amelinckx S, Zhang X. B, Bernaerts D, Zhang X. F, Ivanov V, Nagy J. B, Science 265, 635 (1994) [2] Motojima S, Itoh Y, Asakura S, Iwanaga H, J. Mater. Sci. 30, 5049 (1995) [3] Chen X, Motojima S, J. Mater. Sci. 34 5519 (1999) [4] Motojima S, Asakura S, Kasemura T, Takeuchi S, Iwanaga H, Carbon 34, 289 (1996) [5] S. Yang, X. Chen, and S. Motojima, Carbon 44, 3352 (2004) [6] Chen X Q, Motojima S. Carbon 37, 1817 (1999) [7] Kim M. S, Rodriguez N. M, Baker R. T. K, J. Catal 143, 449 (1993) [8] Amirov I. I and Shumilov A. S, High Energy Chemistry 42, 399 (2008) [9] Asmann M, Heberlein J, Pfender E, Diamond Relat. Mater. 8, 1 (1999) 발표분야(Scope and Theme): 재료화학 발표형식(Presentation Form): 구두(Oral) [ ] 포스터(Poster) [ O ] E-mail address: shkim@silla.ac.kr, tel: +82-51-999-5619, fax: +82-51-999-5335