AFM study of surface phenomena based on C film growth

The surface phenomena of C60 films were investigated using atomic force microscopy AFM.. The films were grown epitaxially on cleaved KBr 001. substrates under various conditions. For thin films -50 nm., single crystalline C60 islands oriented randomly on the substrate due to the lattice mismatch between C60 and substrate. Peculiar features were observed on the thin films, i.e., concave top surface, fivefold twinning and screw dislocation of the islands. The thick films )500 nm.showed different surface phenomena from the thin films. One of these is the spiral growth originated in screw dislocation. We observed both single and double spirals. Another is the surface reconstruction on the thick films. Furthermore, deposition-rate-dependence studies revealed that morphological changes from the 001.faces to the 111.faces depend on an increase in the deposition rates. q1998 Elsevier Science B.V. All rights reserved