Investigation of the interaction between a C60 epitaxial film and a Si(1 1 1)-7×7 surface by electron energy loss spectroscopy

The characteristics of interaction between a monolayer C60 epitaxial film and a Si(1 1 1)-7×7 surface have been studied using electron energy loss spectroscopy (EELS). The EELS measurement in the π–π* transitions region indicates that the interaction between C60 molecules and the Si(1 1 1)-7×7 surface largely modifies the electronic structure of a C60 molecule in the epitaxial C60/Si(1 1 1) system. The C(1s) core electron excitation measurement revealed that this interaction has a covalent character, and that LUMO+1 of a C60 molecule mainly forms hybridized orbitals with dangling bonds of the Si(1 1 1)-7×7 surface.