Nanofabrication of electrodes with sub-5 nm spacing for transport experiments on single molecules and metal clusters

Electron-beam deposition is used to fabricate free-standing carbon nanoelectrodes separated by a gap of less than 5 nm. Fabrication is carried out under direct visual control in an electron microscope. After coating the carbon electrodes with a thin metal film ~e.g., AuPd! such structures can be used to study electrical transport properties of single molecules ~e.g., conjugated polymers! or metal nanoclusters. The fabrication process of the nanowires is described in detail. Furthermore, we suggest electrostatic trapping as a new method to bridge the electrodes with a single conducting nanoparticle in a controlled way. This principle was tested successfully on Pd nanoclusters and carbon nanotubes. © 1997 American Vacuum Society. @S0734-211X~97!13704-0#