Formation of a carbon nanoribbon by spontaneous collapse of a carbon nanotube grown from a γ-Fe nanoparticle via an origami mechanism.

We report a simple method of fabricating graphite nanoribbons by utilizing a self-collapsing mechanism of multi-walled carbon nanotubes during their growth. In the growth process, a nanotube is expelled from a γ-Fe seed nanoparticle, and then collapses spontaneously forming a nanoribbon. Our microscopic analysis of the structures and crystal orientations of γ-Fe nanoparticles and graphite nanoribbons suggests a possible mechanism of the collapse of nanotubes into nanoribbons, an origami mechanism. Our approach can be developed toward the fabrication of bi-layered graphene nanoribbons. Furthermore, the origami mechanism also yields graphitic nano-tetrahedrons.