Electrochemical fabrication and characterization of nanocontacts and nm-sized gaps

Copper nanocontacts and molecular-sized nanogaps were prepared and characterized at electrified solid/liquid interfaces employing lithographic and electrochemical techniques. A dedicated four-electrode potentiostat was developed for controlling the electrochemical fabrication process and for monitoring the electrical characteristics of the nanostructures created. The formation and breaking of Cu nanocontacts exhibits conductance quantization characteristics. The statistical analysis of conductance histograms revealed a preferential stability of nanocontacts with integer values of G₀, with a clear preference for 1 G₀, 2 G₀ and 3 G₀. The growth of molecular-sized gaps shows quantized tunneling current, which is attributed to the discrete nature of Cu atoms, water molecules, and specifically adsorbed ions. PACS 73.23Ad; 73.63.Rt; 82.45.Yz; 85.35.-p