X-RAY-DIFFRACTION AND ELECTRON-SPECTROSCOPY OF EPITAXIAL MOLECULAR C60 FILMS

Films of the new carbon allotrope, molecular C60, also known as Buckminsterfullerene, have been grown on Si(111) substrates by molecular beam epitaxy. The films have been characterized with X-ray 2-THETA diffraction, X-ray photoelectron spectroscopy, Auger electron spectroscopy, and electron energy loss spectroscopy. The diffraction data from oriented films show that close-packed planes of C60 molecules are stacked parallel to the substrate surface but that the correlation length for X-ray scattering is less than 200 angstrom. The electron spectroscopic data show that the C atoms of C60 are essentially sp2-bonded, but there are significant differences with respect to graphite.