SYNCHROTRON RADIATION AND LOW ENERGY ELECTRON DIFFRACTION STUDIES OF ULTRATHIN C60 FILMS DEPOSITED ON Cu(100), Cu(111) AND Cu(110)

Abstract

High resolution K-edge photoemission and X-ray absorption spectroscopies have been used to study the chemical properties of the interface formed with C 60 and Cu . We find that for very thin (0.24–1 monolayers) C 60 films, deposited in ultrahigh vacuum, the Cu substrate plays a role similar to that of K in K 3 C 60 films. Thus Cu donates charge to partially fill the π* 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 C 60 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 C 60 deposition is critical for the ordering of the film.