• 제목/요약/키워드: diamond-stable region

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고압하(高壓下) Ni-C 액상(液相) 속에서의 fullerene형(型) 구상흑연입자(球狀黑鉛粒子)의 형성(形成) (Formation of the Fullerene-type Graphite Spherulites in the Ni-C Liquid under High Pressure)

  • 박종구
    • 분석과학
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    • 제6권2호
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    • pp.149-156
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    • 1993
  • 고온고압하(高溫高壓下)에서의 Ni-C 액상(液相) 중에서 구상흑연입자(球狀黑鉛粒子)의 형성과정을 밝히기 위한 실험적인 관찰을 행하였다. 구상 흑연입자는 다이아몬드 안정역에서 유지하는 동안 안정한 형태로 생성되어 성장하였다. 이 때의 구상 흑연입자는 다결정형태(多結晶形態)가 아닌 연속적으로 성장한 많은 결함을 포함하는 단결정형태(單結晶形態)(fullerene형(型))를 하고 있었다. 표면분석기(表面分析機)(Auger electron spectroscope) 및 고분해능(高分解能) 투과전자현미경(透過電子顯微鏡)을 이용한 분석결과 구상 흑연 입자는 $sp^2$$sp^3$ 결합을 갖는 탄소원자가 혼재(混在)되어 있는 결정상태임이 밝혀졌다. 다이아몬드 안정역으로부터 흑연 안정역으로 압력이 감소함에 따라 흑연입자의 모양이 구형(球形)에서 평판형(平板形)으로 연속적으로 변해가는 것이 관찰되었다. 다이아몬드 안정역에서 형성되는 구상 흑연입자는 $sp^3$ 결합을 가지는 탄소 원자의 안정적인 존재 때문인 것으로 해석되었다. 많은 결함을 포함하는 큰 크기의 fullerene형(型) 구상 흑연입자가 연속적으로 성장하는 사실은 Kroto가 예측한 대형 fullerene의 성장과정을 실험적으로 뒷받침해 주는 결과라 생각한다.

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Growth of Hexagonal Boron Nitride Thin Films on Silicon Using a Single Source Precursors

  • Boo, Jin-Hyo;Lee, Soon-Bo;Casten Rohr;Wilson Ho
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 1998년도 제14회 학술발표회 논문개요집
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    • pp.120-120
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    • 1998
  • Boron nitride (BN) films have attracted a growing interest for a variety of t technological applications due to their excellent characteristics, namely hardness, c chemical inertness, and dielectrical behavior, etc. There are two crystalline phases 1551; of BN that are analogous to phases of carbon. Hexagonal boron nitride (h-BN) has a a layered s$\sigma$ucture which is spz-bonded structure similar to that of graphite, and is t the stable ordered phase at ambient conditions. Cubic boron nitride (c-BN) has a z zinc blende structure with sp3-bonding like as diamond, 따ld is the metastable phase a at ambient conditions. Among of their prototypes, especially 삼Ie c-BN is an i interesting material because it has almost the same hardness and thermal c conductivity as di없nond. C Conventionally, significant progress has been made in the experimental t techniques for synthesizing BN films using various of the physical vapor deposition 밍ld chemical vapor deposition. But, the major disadvantage of c-BN films is that t they are much more difficult to synthesize than h-BN films due to its narrow s stability phase region, high compression stress, and problem of nitrogen source c control. Recent studies of the metalorganic chemical vapor deposition (MOCVD) of I III - V compound have established that a molecular level understanding of the d deposition process is mandatory in controlling the selectivity parameters. This led t to the concept of using a single source organometallic precursor, having the c constituent elements in stoichiometric ratio, for MOCVD growth of 삼Ie required b binary compound. I In this study, therefore, we have been carried out the growth of h-BN thin f films on silicon substrates using a single source precursors. Polycrystalline h-BN t thin films were deposited on silicon in the temperature range of $\alpha$)() - 900 $^{\circ}$C from t the organometallic precursors of Boron-Triethylamine complex, (CZHs)3N:BRJ, and T Tris(dimethylamino)Borane, [CH3}zNhB, by supersonic molecular jet and remote p plasma assisted MOCVD. Hydrogen was used as carrier gas, and additional nitrogen w was supplied by either aDlIDonia through a nozzle, or nitrogen via a remote plasma. T The as-grown films were characterized by Fourier transform infrared spectroscopy, x x-ray pthotoelectron spectroscopy, Auger electron spectroscopy, x-ray diffraction, t transmission electron diffraction, optical transmission, and atomic force microscopy.roscopy.

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