Published online by Cambridge University Press: 15 February 2011
High quality C60 films are grown on surfaces of (111) oriented noble metal substrates (i.e., Au, Ag, and Cu) by using a molecular beam deposition method. The structures of these films are compared with each other on substrates that are prepared to have similar in-plane mosaic widths (σ1.25*) as determined by their x-ray diffraction scans. The in-plane structures of these films are studied for substrate temperatures ranging from σ110 to 290°C. Although most materials grow in high symmetry small-lattice-mismatch in-plane orientations, C60 films (depending on their growth temperatures) grow in orientations that are poorly lattice matched with their Au(111) and Ag(111) substrates. In these orientations, C60 structures can be lattice matched only over large unit cells, forming “long-period ” structures. These “long-period ” structures coexist with “commensurate” structures that are almost perfectly lattice matched on twheitshe osur bpsrterdaotems.i naOten Au(111) substrates, a structural transition is observed between two distinct long-period structures (at Tc, σ150 °C). Although Au and Ag have similar lattice spacings, this transition is absent on Ag(111) substrates. The question of orientational epitaxy for C60 layers is examined in the context of several well-known systems in condensed matter physics.