SYNCHROTRON RADIATION AND LOW-ENERGY ELECTRON-DIFFRACTION STUDIES OFULTRATHIN C-60 FILMS DEPOSITED ON CU(100), CU(111) AND CU(110)

High resolution K-edge photoemission and X-ray absorption spectroscopies have been used to study the chemical properties of the interface formed with C60 and Cu. We find that for very thin (0.24 - 1 monolayers) C60 films, deposited in ultrahigh vacuum, the Cu substrate plays a role similar to that of K in K3C60 films. Thus Cu donates charge to partially fill the pi* LUMO band, and the C (1s) core level shifts due to charge transfer. For monolayer coverage the C (1s) core-level line shape is broad. Low energy electron diffraction studies of C60 on Cu(100), Cu(111) and Cu(110) show that well ordered overlayers of thickness > 2 monolayers can be formed on all three Cu surfaces, but single-domain epitaxy is achieved only on Cu(111). The substrate temperature during C60 deposition is critical for the ordering of the film.