Spectroscopic investigation of C_60 interaction with GaAs and Bi

We present a spectroscopic study of the interaction od a C_60 film with GaAs (110) surface and with a semimetallic overlayer (Bi). The characterization of the sample was carried out by means of different elelctron spectroscopies, such as ELS and UPS. We found a decrease in the intensity of the HOMO peaks in the valence band as the C_60 film thickness increases and the onset of metallic character in the Bi/C_60 even at small Bi coverages. Previously obtained results on pure C_60 fils, like the shape of the valence band and the low energy electronic transition across the fundamental gap, are confirmed.