Credit: © 2006 ACS

The ability to create arrays of organic nanostructures on surfaces with long-range order and uniform size could have applications in micro- and optoelectronic devices. One of the most promising methods for making such arrays is to rely on the self-assembly of molecules on 'vicinal' surfaces that already possess long-range order in, for example, the form of terraces and steps. Researchers at the Swiss Federal Laboratories for Materials Testing and Research and Liverpool University in the UK have now used this approach to grow ordered arrays of fullerene nanochains on a gold surface. Each nanochain consists of just four or five fullerene molecules.

Roman Fasel and co-workers1 prepared gold substrates with a (11 12 12) structure — which naturally forms a rectangular superlattice — and sublimated the fullerene molecules onto the surface. Using scanning tunnelling microscopy and low-energy electron diffraction, they observed that the nanochains only formed at the lower step edges of the gold surface. The electron-rich regions near these edges are thought to preferentially adsorb the fullerene molecules, which are electron acceptors, leading to the formation of arrays that perfectly reproduce the periodicity of the gold template.