On-surface polymerization on a semiconducting oxide: aryl halide coupling controlled by surface hydroxyl groups on rutile TiO2(011).

Based on scanning tunneling microscopy experiments, we show that the covalent coupling of aryl halide monomers on the rutile TiO2(011)-(2 × 1) surface is controlled by the density of surface hydroxyl groups. The efficiency of the polymerization reaction depends on the level of surface hydroxylation, but the presence of hydroxyl groups is also essential for the reaction to occur.

STM tip-assisted engineering of molecular nanostructures: PTCDA islands on Ge(001):H surfaces.

Islands composed of perylene-3,4,9,10-tetracarboxylic dianhydride (PTCDA) molecules are grown on a hydrogen passivated Ge(001):H surface. The islands are studied with room temperature scanning tunneling microscopy and spectroscopy. The spontaneous and tip-induced formation of the top-most layer of the island is presented. Assistance of the scanning probe seems to be one of the factors that facilitate and speed the process of formation of the top-most layer.