Epitaxial growth of C60 on Ag(110) studied by scanning tunneling microscopy and tunneling spectroscopy

Abstract

Using a scanning tunneling microscope, the growth of C60 on Ag(110) is explored. The substrate influences the natural tendency of the fullerene molecules to pack closely and an overlayer system with twofold rotational symmetry is formed: Ag(110)c(4×4)C60. This represents a distorted close-packed configuration for the C60 molecules, where the nearest-neighbor distance observed in bulk C60 is maintained. Initial island growth occurs on terrace sites away from substrate step edges, which bunch with increasing fullerene coverage. Above monolayer coverage, C60 grows epitaxially, maintaining twofold rotational symmetry. Tunneling spectroscopy is used to explore differences between the electronic structure in the monolayer and multilayer regimes. © 1994 The American Physical Society.