Growth of ordered C60 islands on TiO2(110)

Abstract

Non-contact atomic force microscopy is used to studyC60 molecules depositedon the rutile TiO2(110) surface in situ at room temperature. At submonolayer coverages, moleculesadsorb preferentially at substrate step edges. Upon increasing coverage,ordered islands grow from the decorated step edges onto the lower terraces.Simultaneous imaging of bridging oxygen rows of the substrate and theC60 island structurereveals that the C60 molecules arrange themselves in a centered rectangular superstructure, with the moleculeslying centered in the troughs formed by the bridging oxygen rows. Although theTiO2(110) surface exhibits a high density of surface defects, the observedC60 islands are of high order. This indicates that theC60 intermolecular interaction dominates over the molecule–substrate interactions thatmay cause structural perturbations on a defective surface. Slightly protrudingC60 strands on the islands are attributed to anti-phase boundaries due to stacking faultsresulting from two islands growing together.