Structuring of surfaces using atomic force microscopy (AFM) is an elegant way for the generation of one- and two-dimensional nanostructures. One way to realize this is the local electrochemical oxidation of the substrate under ambient conditions. Here a negative voltage is applied to the tip with respect to the sample and the water in the miscues formed between tip and substrate due to the surrounding humidity is partly electrolysed. The formed oxyanions are migrating to the surface where an oxidation of the substrate material takes place. This method allows the creation of structures down to 10 nm in width.

A very suitable system for this method is the highly crystalline silicon. The properties of such surfaces can be easily tuned by self-assembled monolayers. These monolayers consist of pure as well as terminal functionalized alkyl chains and are covalently bound to the silicon substrate by silicon – carbon junctions. The monolayer influences the oxidation process e.g. due to its different surface energies.

For selective attachment of functional molecules or materials as nanoaggregates various interactions can be used. A covalent interaction of dye molecules for example can be realised by functionalization of the formed oxide by silane monolayers with coupling groups like an amino group, which is then used to bind dye molecules via peptide linking. Also non-covalent binding mechanisms like hydrophobic or electrostatic interactions allow the formation of functional nanostructures.