title: In situ observations of catalyst dynamics during surface-bound carbon nanotube nucleation.
abstract: We present atomic-scale, video-rate environmental transmission electron microscopy and in situ time-resolved X-ray photoelectron spectroscopy of surface-bound catalytic chemical vapor deposition of single-walled carbon nanotubes and nanofibers. We observe that transition metal catalyst nanoparticles on SiOx support show crystalline lattice fringe contrast and high deformability before and during nanotube formation. A single-walled carbon nanotube nucleates by lift-off of a carbon cap. Cap stabilization and nanotube growth involve the dynamic reshaping of the catalyst nanocrystal itself. For a carbon nanofiber, the graphene layer stacking is determined by the successive elongation and contraction of the catalyst nanoparticle at its tip.
authors.affiliation: Department of Engineering, University of Cambridge, Cambridge CB3 0FA, UK. sh315@cam.ac.uk
authors.forename: Stephan
authors.initials: S
authors.lastname: Hofmann
authors.forename: Renu
authors.initials: R
authors.lastname: Sharma
authors.forename: Caterina
authors.initials: C
authors.lastname: Ducati
authors.forename: Gaohui
authors.initials: G
authors.lastname: Du
authors.forename: Cecilia
authors.initials: C
authors.lastname: Mattevi
authors.forename: Cinzia
authors.initials: C
authors.lastname: Cepek
authors.forename: Mirco
authors.initials: M
authors.lastname: Cantoro
authors.forename: Simone
authors.initials: S
authors.lastname: Pisana
authors.forename: Atlus
authors.initials: A
authors.lastname: Parvez
authors.forename: Felipe
authors.initials: F
authors.lastname: Cervantes-Sodi
authors.forename: Andrea C
authors.initials: AC
authors.lastname: Ferrari
authors.forename: Rafal
authors.initials: R
authors.lastname: Dunin-Borkowski
authors.forename: Silvano
authors.initials: S
authors.lastname: Lizzit
authors.forename: Luca
authors.initials: L
authors.lastname: Petaccia
authors.forename: Andrea
authors.initials: A
authors.lastname: Goldoni
authors.forename: John
authors.initials: J
authors.lastname: Robertson