Theory and experiment agree: single-walled carbon nanotube caps grow catalyst-free with chirality preference on a SiC surface.
High-temperature quantum chemical molecular dynamics simulations have been performed on model systems of thin SiC crystal surfaces with two graphene sheets placed on top of either C or Si face. In agreement with experiment, we find that (a) the C-face-attached graphene layer warps readily to form small diameter, stable nanocaps, suitable for further perpendicular growth of nanotubes, (b) the Si-face-attached graphene sheet does not readily wrap and forms more volatile Si-graphene bonds, and (c) C face nanocaps appear to anneal to dome-shape structures with zigzag chirality.
Irle
Stephan
S
Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA. sirle@emory.edu
Wang
Zhi
Z
Zheng
Guishan
G
Morokuma
Keiji
K
Kusunoki
Michiko
M