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 2θ 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 Å. The electron spectroscopic data show that the C atoms of C₆₀ are essentially sp²-bonded, but there are significant differences with respect to graphite.