Browsing by Author "Kang, JungHo"
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Item Characterization of functionalized carbon nanotubes and graphite(2008) Kang, JungHo; Kelly, Kevin F.Graphene and carbon nanotubes have drawn much attention in the last decade, and functionalization of these materials is considered a great technique for manipulating them. In this project, we mainly investigated functionalized double-wall carbon nanotube and functionalized graphite. Due to the unique physical structure of double-wall carbon nanotubes (DWNTs), the outer tube can be chemically functionalized while the inner tube is left in pristine condition. The diameter of bare DWNTs is around 2-3 nm as measured by scanning tunneling microscopy (STM), but fluorinated DWNTs possess much larger diameters, from 3-10 nm, due to a stronger electronic interaction. In addition to imaging the as prepared material, the material was imaged after annealing at temperatures up to 1000 K. Due to the defluorination, the diameter is decreased to that of the initial bare DWNTs and atomic resolution of the lattice was recovered. In addition, it was possible to observe the initial and final structures on the same nanotubes and the evolution of their associated defect structures. Lastly, Raman spectroscopy was employed to confirm the defluorination by revealing the recovery of the radial breathing mode which disappeared upon fluorination. Also, we investigate the epoxidation mechanism on graphite surfaces with STM and Raman spectroscopy, and our results indicate that the functionalzation occurs on the edges, not on the basal plane as reported previously.Item Investigation of graphitic nanostructures and nanomachines(2010) Kang, JungHo; Kelly, Kevin F.Carbon allotropes such as nanotubes, graphene, and buckyball all preserve the same lattice structure. However, their electronic properties are very different depending on their dimensionality. These nanostructures can be functionalized with other chemical groups or can be used to form complicated molecular structures. By using scanning tunneling microscopy and Raman spectroscopy, the functionalization of carbon nanotubes with fluorine was studied as a potential route to tailoring the electrical and chemical properties of carbon nanotubes, and functionalization and exfoliation techniques of graphite without inducing basal plane defects were investigated. Also, building upon our previous research on nanocars, nanodragsters combining buckyball and p-carborane wheels were studied with scanning tunneling microscopy. Unlike its predecessors, a nanodragster can show interesting motions even at room temperature as well as at elevated temperatures.