NER: Controlled Synthesis of Carbon Nantotubes with Desired Properties

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AbstractProposal Title: NER: Controlled Synthesis of Carbon Nanotubes with Desired Properties Proposal Number: CTS-0508434Principal Investigator: Renu SharmaInstitution: Arizona State UniversityAnalysis (rationale for decision):There is great interest in using carbon nanotubes as components in micromachines, scanning probes, nanocircuits and as elements of biosensors since their structural variations give rise to a diverse range of mechanical and electrical properties. Synthesis of sufficient quantities of nanotubes with a targeted structure and set of properties is still a challenge. Carbon nanotubes will be synthesized by controlled in situ catalytic chemical vapor deposition (CVD) in an environmental high-resolution transmission electron microscope (ETEM). The catalyst will also be prepared in the same instrument by electron beam induced deposition. With control over the catalyst dispersion and the nanotube synthesis conditions, as well as the ability to observe and physically characterize the emerging structures at the sub-nanoscale, new insights will be gained into the nanotube synthesis process. First principles electronic structure calculations, in conjunction with structural models, will explore how catalyst particle orientation may contribute to the growth direction and growth rate. The diffusion of carbon through and on the surface of the catalyst particles will also be modeled. The research goal is to elucidate ways to selectively synthesize desirable types of CNT including single-walled CNTs (SWCNTs).The selective fabrication of carbon nanotubes would be an important step towards the broader goal of using nanotubes in nanoscale devices. For example, the techniques developed will be valuable in the direct synthesis of field emitters for flat panel displays or 3-D networks for semiconductor devices. Also, electron beam induced deposition can be used to fabricate arrays of quantum dots. Combinatorial catalysis characterization techniques developed here will also be useful for studying catalysis at the atomic level at typical reaction temperatures, and will have impact in the design of catalysts for many applications. Video movies showing growth mechanisms, combined with models, form invaluable visual aids for undergraduate nanotechnology education as well as for a K-12 outreach program.