Self-organized growth of molecular nanostructures at metal surfaces

J.V. Barth, J. Weckesser, L. Burgi, O. Jeandupeux and K. Kern Institut de Physique Exprimentale, Ecole Polytechnique Fdrale Lausanne, CH-1015 Lausanne Temperature controlled scanning tunneling microscopy (STM) provides novel insight into molecular bonding, surface mobility and ordering at the atomic level. This will be illustrated by observations of 4-trans-2-(pyrid-4-yl-vinyl) benzoic acid (PVBA) on Pd and Ag surfaces. PVBA is a rigid, large organic molecule (m=225 amu) designed for optical films.

The thermal hopping of PVBA molecules can be directly monitored revealing their diffusion characteristics, which depend strongly on the chemical nature and the symmetry of the substrate surface.

The interplay between the lateral molecular interactions and the mobility can be employed for molecular self-assembly.

By exploiting the complex nature of molecular interactions, striking new molecular nanostructures such as extended chains can be obtained.