Adsorption and film growth of C₆₀ on the GaAs(001) 2×6 surface by molecular-beam epitaxy

Field ion scanning tunneling microscopy was employed to investigate C₆₀ film growth on a GaAs(001)-2×6 surface prepared by molecular-beam epitaxy. The corrugated potential of the 2×6 substrate forces the first monolayer structure to be strongly modified, resulting in formation of a "double-chain" commensurate structure. A stronger interaction between C₆₀ and Ga versus C₆₀ and As was observed. This interaction of C₆₀ and the substrate, however, is limited for two to three monolayers at the interface and the competing intermolecular interaction governs the three-dimensional growth of multiple-layer C₆₀ crystalline film of the (111) orientation with a high density of screw dislocations.