The surface ordering of copper phthalocyanine (CuPc) molecules deposited onto an InSb(001) c(8 x 2) reconstructed surface was studied using scanning tunneling microscopy, non-contact atomic force microscopy and low-energy electron diffraction. It was found that at room temperature the CuPc molecules were only weakly bound to the InSb surface and the adjacent molecules and consequently they were relatively mobile at sub-monolayer coverage. scanning tunnelling microscopic images show that at the initial stages of growth molecules were assembled in ordered molecular chains parallel to the surface reconstruction rows, i.e. along the [110] crystallographic direction. Furthermore, adsorption of the molecules at step edges was observed. At coverages below 1ML molecules diffuse at the surface and formed two-dimensional islands, which led to an additional characteristic (n x 3) low-energy electron diffraction pattern indicating one-dimensional ordering within the molecular chains. High-resolution scanning tunnelling microscopy imaging at negative sample bias reveals a unique structure of the molecular contrast which could be related to the highest occupied molecular orbital of the individual CuPc molecules. For CuPc monolayer coverage sub-molecular resolution was also obtained for non-contact atomic force microscopic imaging. Finally, examples of single molecule manipulation by the scanning tunnelling microscopy tip were given.

Copper Phthalocyanine Molecules on an InSb(001) c(8 x 2) Surface Studied by Ultra-High-Vacuum STM and Non-Contact AFM. A.Tekiel, M.Goryl, M.Szymonski: Nanotechnology, 2007, 18[47], 475707 (7pp)