AVS 51st International Symposium
    Nanometer-scale Science and Technology Tuesday Sessions
       Session NS-TuP

Paper NS-TuP11
Metal Catalyzed Carbon Nanotube Synthesis by Chemical Vapor Deposition: A First Principles Study of CNT Nucleation and Growth

Tuesday, November 16, 2004, 4:00 pm, Room Exhibit Hall B

Session: Poster Session
Presenter: S.H. Lee, The University of Texas at Austin
Authors: S.H. Lee, The University of Texas at Austin
G.S. Hwang, The University of Texas at Austin
Correspondent: Click to Email
Carbon nanotubes (CNTs) have numerous potential applications ranging from chemical and biological sensors to future electronic devices. Their shape, atomic configuration, and chemical composition could be tailored by tuning process parameters such as temperature and feed gas composition. Such atomic scale control is essential for the development of viable novel chemical, biological and electronic devices. However, still very little is known about underlying growth mechanisms, due largely to a difficulty in direct measurement of complex physical and chemical phenomena occurring during actual CVD processing. While current experimental techniques are still limited to providing complementary real space information, the interplay between experiment and theory will contribute to uncovering complex CNT growth mechanisms and subsequently achieving precise control of their physical and chemical properties. Using density functional theory calculations, we have investigated the initial stage of Ni-catalyzed CNT growth with a feed gas of C2H2/NH3. In this talk, we will present i) decomposition of C2H2 and NH3 which is a strong function of the surface facet of catalysts, ii) hydrogen etching of carbon, iii) diffusion dynamics of decomposed carbon atoms, and iv) formation mechanisms of ring structures from small hydrocarbon species. We will also discuss when the atomic configuration of CNTs will be determined, such as zigzag and armchair structures.