No abstract

Assembling and aligning molecules on surfaces: By creating a suitable O–Cu nanotemplate on a Cu(110) surface, “Lander” molecules were successfully assembled into long, well‐ordered one‐dimensional chains (see picture). By controlling the ratio between the length of the molecules and the width of bare Cu stripes, the molecules can be forced to align along the specific direction of the Cu stripes.

A surface potential measurement method using amplitude-modulation and heterodyne techniques is proposed. The effect of the stray capacitance between a cantilever and a sample in Kelvin probe force microscopy and the electrostatic force spectroscopy measurements are almost completely removed, because the distance (z) dependence of the modulated electrostatic force increases from 1/z to1/z2. This method improves the sensitivity of short range forces and reduces the surface potential measurement crosstalk that is induced by topographic feedback. This method has the advantage of high potential sensitivity due to the high cantilever Q value under vacuum. Quantitative surface potential measurements are demonstrated.

The adsorption of a large organic molecule, named Lander, has been studied on a Cu͑110͒ substrate by scanning tunneling microscopy ͑STM͒. At low temperatures three different conformations of the molecule are observed on the flat surface terraces. At room temperature the Lander molecules are highly mobile and anchor preferentially to step edges. There the molecules cause a rearrangement of the Cu step atoms leading to the formation of Cu nanostructures that are adapted to the dimension of the molecule, as revealed directly by STM manipulation experiments. Upon annealing to 500 K the molecules order at higher coverages partially into small domains. In all cases the exact adsorption conformation of the molecules was identified through an interplay with elastic scattering quantum chemistry calculations.

By means of STM imaging and manipulation, we show that violet Lander (VL) molecules (C 108 H 104 ) act as nanoscale templates at the Cu(110) step edges, creating nanostructures to which the VLs are anchored. These nanostructures are longer and sometimes wider than those created by the related single Lander (SL) molecules due to the slightly different shape and size of the VL molecules. These results illustrate the possibility of controlling the formation of nanostructures on a surface on the atomic scale by means of a rational molecular design.