Atomic Force Microscope Studies of Fullerene Films: Highly Stable C60 fcc (311) Free Surfaces
ERIC J. SNYDER 1,
MARK S. ANDERSON 2,
WILLIAM M. TONG 1,
R. STANLEY WILLIAMS 1,
SAMIR J. ANZ 1,
MARCOS M. ALVAREZ 1,
YVES RUBIN 3,
FRANÇOIS N. DIEDERICH 3, and
ROBERT L. WHETTEN 1
1 Department of Chemistry and Biochemistry, and Solid State Science Center, University of California, Los Angeles, CA 90024
2 Jet Propulsion Laboratory, Pasadena, CA 91109
3 Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90024
Atomic force microscopy and x-ray diffractometry were used to study 1500 Å-thick films of pure C60 grown by sublimation in ultrahigh vacuum onto a CaF2 (111) substrate. Topographs of the films did not reveal the expected close-packed structures, but they showed instead large regions that correspond to a face-centered cubic (311) surface and distortions of this surface. The open (311) structure may have a relatively low free energy because the low packing density contributes to a high entropy of the exposed surface.
Submitted on April 29, 1991
Accepted on June 10, 1991
