Physics of Supramolecular Systems, University of Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany
The main goals of molecular nanotechnology are the fabrication, manipulation and application of macro- and supramolecular objects with nanometer dimensions. We use a combination of molecular self-assembly and electron beam lithography for the building of 1-2 nm thin stable carbon nanosheets. The nanosheets were made by irradiation-induced cross-linking of aromatic self-assembled monolayers and their subsequent release from the substrate. They can then be transferred onto arbitrary surfaces, including metals, insulators, polymers, and porous materials. We have found that nanosheets are mechanically and thermally (up to 1000K in UHV) stable.
A first technological application of carbon nanosheets is their use as ultrathin sample supports for transmission electron microscopy (TEM). We tested their applicability by placing Co and Au nanoparticles on 1.6 nm thick nanosheets. The corresponding TEM images show significant improvements over a conventional 15 nm thick film. The contrast of Co and Au clusters, as well as of single diffusing gold atoms is much higher on the nanosheet than on any conventional support.