Seed crystals and catalyzed epitaxy of single-walled carbon nanotubes

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dc.contributor.advisorSmalley, Richard E.en_US
dc.creatorWang, Yuhuangen_US
dc.date.accessioned2009-06-04T08:49:01Zen_US
dc.date.available2009-06-04T08:49:01Zen_US
dc.date.issued2004en_US
dc.description.abstractThis thesis demonstrates the continued growth of single-walled carbon nanotubes (SWNTs) from seeded SWNTs in a way analogous to epitaxy or cloning; that is, the SWNTs grow as a seamless extension to the existing seeded SWNTs and have the same diameter and chirality as those of the SWNT seeds. The experiments were carried out in three key steps, including: (1) preparing a macroscopic array of open-ended SWNTs; (2) reductively docking transition metals as a catalyst to the nanometer-sized open ends; and then (3) heating the whole up to 700--850°C in the presence of a carbon feedstock such as ethanol or ethylene. The resulting SWNT ropes inherit the diameters and chirality from the seeded SWNTs, as indicated by the closely matched frequencies of Raman radial breathing modes before and after the growth. As a control, only sparse nanotubes grew from closed-ended SWNTs, ruling out spontaneous nucleation as a dominating mechanism in our experiments. This experiment proved for the first time the growth of SWNTs can be separated from the nucleation step. The ability to separate the typically inefficient nucleation step from the growth of SWNTs and to restart the growth opens the possibility of amplifying SWNTs with only the desired (n, m). The success in the continued growth was enabled with the creation of macroscopic arrays of open-ended SWNTs from a neat SWNT fiber. A variety of techniques including cryo-microtoming and surface etching chemistry have been developed to produce a macroscopic (∼1200mum2), aligned, and clean---largely free of amorphous carbon, oxides, and metal residuals---SWNT substrate with open-ended SWNTs aligned along the fiber axis. Alternatively, the fiber was milled perpendicular to the fiber axis with a gallium focused ion beam to produce a planar, free-standing, ultra-thin, "bed-of-nails" SWNT membrane---a single layer of parallel SWNTs densely packed and aligned along the normal of the membrane.en_US
dc.format.extent186 p.en_US
dc.format.mimetypeapplication/pdfen_US
dc.identifier.callnoTHESIS CHEM. 2005 WANGen_US
dc.identifier.citationWang, Yuhuang. "Seed crystals and catalyzed epitaxy of single-walled carbon nanotubes." (2004) Diss., Rice University. <a href="https://hdl.handle.net/1911/18834">https://hdl.handle.net/1911/18834</a>.en_US
dc.identifier.urihttps://hdl.handle.net/1911/18834en_US
dc.language.isoengen_US
dc.rightsCopyright is held by the author, unless otherwise indicated. Permission to reuse, publish, or reproduce the work beyond the bounds of fair use or other exemptions to copyright law must be obtained from the copyright holder.en_US
dc.subjectChemistryen_US
dc.subjectMolecular physicsen_US
dc.subjectEngineeringen_US
dc.subjectMaterials scienceen_US
dc.titleSeed crystals and catalyzed epitaxy of single-walled carbon nanotubesen_US
dc.typeThesisen_US
dc.type.materialTexten_US
thesis.degree.departmentChemistryen_US
thesis.degree.disciplineNatural Sciencesen_US
thesis.degree.grantorRice Universityen_US
thesis.degree.levelDoctoralen_US
thesis.degree.nameDoctor of Philosophyen_US
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