Scanning Force Microscopy of Conjugated Anisotropic Thin Films Grown in High-Vacuum

Scanning force microscopy has been used to investigate the quantitative aspects of the morphology transition from isotropic grains to anisotropic lamellae in sexithienyl thin films. 2-D islands made of few molecular layers grow up to a critical thickness which depends on the deposition temperature, then the film grows as a rough 3-D surface. A statistical analysis of SFM data yields domain size and shape distributions, diffusional barriers, roughness scaling parameters, and orientational ordering. This framework provides an explanation for the mechanism of growth in terms of competition between diffusion and capture.