Graphene-based carbon micro-/nano-cones were prepared by depositing pyrolytic carbon onto individual carbon nanotubes as supports using a specific chemical vapor deposition process. They were investigated by means of high-resolution scanning electron microscopy, low-voltage aberration-corrected transmission electron microscopy, Raman spectroscopy, and molecular dynamics modeling. While the graphenes were confirmed to be perfect, the cone texture was determined to be preferably scroll-like, with the scroll turns being parallel to the cone axis. Correspondingly, many of the concentrically displayed graphenes (actually scroll turns) exhibit the same helicity vector. When radii of curvature are large enough, this could allow for coherent stacking to locally take place in spite of the lattice shift induced by the curvature. A particular care was taken on investigating the cone apexes, in which a specific type of graphene termination was observed, here designated as the “zip” defect. Calculations determined a plausible stable structure that such a defect type may correspond to. This defect was found to generate a very low Raman I_D/I_D′ band ratio (1.5), for which physical reasons are proposed. Combining our results and that of the literature allowed proposing an identification chart for a variety of defects able to affect the graphene lattice or edges.

中文翻译：

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碳纳米管支撑的碳锥的纹理、纳米纹理和结构

基于石墨烯的碳微/纳米锥是通过使用特定的化学气相沉积工艺将热解碳沉积到作为载体的单个碳纳米管上制备的。通过高分辨率扫描电子显微镜、低压像差校正透射电子显微镜、拉曼光谱和分子动力学模型对它们进行了研究。虽然石墨烯被证实是完美的，但锥形纹理被确定为最好的卷轴状，卷轴转角平行于锥轴。相应地，许多同心显示的石墨烯（实际上是滚动的）表现出相同的螺旋矢量。当曲率半径足够大时，尽管由曲率引起的晶格位移，这可以允许局部发生相干堆叠。在研究锥形顶点时特别小心，在其中观察到特定类型的石墨烯终止，这里指定为“zip”缺陷。计算确定了这种缺陷类型可能对应的合理稳定结构。发现此缺陷会产生非常低的拉曼I _D / I _D'带比 (1.5)，为此提出了物理原因。结合我们的结果和文献的结果，可以为能够影响石墨烯晶格或边缘的各种缺陷提出识别图表。