SPIRAL GROWTH OF C-60

We have observed the spiral growth of C60 grown on cleaved graphite using atomic force microscopy. Triangular terraces in the spirals consist of a monolayer of C60 having a 10 angstrom step height which agrees well with (111) lattice constant of fcc-C60. One of the characteristic features of the C60 spiral is the presence of a line defect running from the spiral core and crossing the spiral terraces. As a result, the original helicoid plane transforms into a stack of terraces. We think the C60 spiral growth is terminated by the introduction of a line defect at the early stages of the film growth, resulting from the weak van der Waals forces.