Investigation of interface between fullerene molecule and Si(111)-7×7 surface by noncontact scanning nonlinear dielectric microscopy

Abstract

Fullerene (C60) molecules deposited on Si(111)-7×7 reconstructed (7×7) surface were investigated by noncontact scanning nonlinear dielectric microscopy (NC-SNDM) under ultrahigh vacuum conditions. Both topography and induced electric dipole moment of individual C60 molecules were successfully resolved with molecular-scale resolution. Charge transfer from the Si dangling bonds to the C60 molecule occurs and induces an electric dipole moment at almost all C60 sites. On the application of an alternating voltage, the downward electric dipole moment is nonlinearly modulated due to the electric property at the interface. The NC-SNDM technique can thus detect the electric dipole moment induced at interface between the C60 molecule and the Si adatom in 7×7 surface by the charge transfer from the Si adatom to C60 molecule.