Thermal-dependent electronic structure at the interface of C₆₀-adsorbed Si(111)-(7 × 7) surface

We report here the temperature-dependent measurements of the valence spectra, and the C 1s and the Si 2p core-level spectra of the C₆₀ adsorbed Si(111)-(7 × 7) surface, using photoelectron spectroscopy. At 300 K the valence spectra show the physisorption of most C₆₀ molecules for a one monolayer C₆₀ film. After annealing the sample at 1120 K the molecular orbitals disappear due to the breakdown of the C₆₀ cage. The C 1s and Si 2p core-level spectra obtained at the same temperature indicate the progress of SiC formation at the interface between C₆₀ and the Si(111) surface. After annealing at 1170 K, the formation of SiC islands is confirmed by the binding energies of the peaks observed in the valence and C 1s core-level spectra.