C60 SINGLE-CRYSTAL FILMS ON GAAS INAS(001) SURFACES/

In this pape, we report a scanning tunnelling microscopy study of C60 thin film growth on the GaAs(001) As-rich 2 x 6 and InAs(001) In-rich 4 x 2 surfaces prepared by molecular beam epitaxy. On the 2 x 6-As sur face, the corrugated potential of the 2 x 6 substrate forces the first monolayer structure to be strongly modified resulting in formation of a 'double-chain' commensurate structure. C60-substrate interaction, h owever, is limited to 2-3 monolayers at the interface and the competin g intermolecular interaction governs the 3-dimensional growth of multi ple-layer C60 FCC crystalline film on the InAs(001). In 4 x 2 surface, the C60 molecule is very mobile even at room temperature. The intermo lecular interaction is significant and overcomes the substrate corruga ted potential, and 2-dimensional islands with quasi-hexagonal close-pa cking form even at submonolayer coverage.