More recently, single-molecule-measurement experiments have been developed that are bringing experimenters a better look at molecular conductance. These fall under the categories of scanning probe, which involves fixed electrode, and mechanically formed junction techniques. One example of a mechanically formed junction experiment involves using a movable electrode to make contact with and then pull away from an electrode surface coated with a single layer of molecules. As the electrode is removed from the surface the molecules that had bonded between the two electrodes begin to detach until eventually one molecule is connected. The atomic-level geometry of the tip-electrode contact has an effect on the conductance and can change from one run of the experiment to the next so a histogram approach is required. Forming a junction in which the precise contact geometry is known has been one of the main difficulties with this approach.
Read more about this topic: Molecular Conductance