C60 thin films on Ag(001): an STM study Original Research Article

The structure of submonolayer C60 films deposited on Ag(001) is studied as a function of the substrate temperature in the range 100–700 K. Morphological aspects such as island shape and preferential nucleation sites are in agreement with the theory of submonolayer deposition. A peculiar irreversible transition which leads to the onset of brightness differences between molecules of the same film is observed at around 300 K. This effect is ascribed to electronic differences due to non-equivalent orientation of the C60 molecules on the surface rather than to morphological differences induced by a surface reconstruction.