Manufacturing ‘made to measure’ atomic scale electrodes
1 min read
Researchers have shown that it is possible to determine and control the number of atoms in contact between a molecule and a metal electrode of copper, at the same time as the electric current passing through the union being recorded.
The findings, published in the Nature Nanotechnology journal, reveal the changes that the electric current flowing through a molecular union (metal/molecule/metal) undergoes, depending on the area of contact uniting the molecule to the metallic electrodes.
Teams from Donostia-San Sebastian and the University of Kiel found that by changing the number of atoms in contact with the molecule one by one, it goes from a low state (bad contact) to another, higher one (good contact) of conduction. With bad contact the current is limited by the area of contact, while with good contact the current is limited by the intrinsic properties of the molecule.
The researchers say are keen to address one of the key problems in nanotechnology - the formation of electrical contacts at an atomic scale. This demands detailed characterisation of the current flowing through extremely small circuits, which are so small that their components can be individual atoms or molecules.
It is this miniature nature of the system, of typically nanometric dimensions (1metro = 1000million nanometers), where the difficulty of this yet unresolved problem is said to arise. In unions formed by a single molecule, the number of individual atoms making up the contact and their positions are crucial when determining the electric current that is flowing. The researchers claim there has not yet been an experiment where it has been possible to control these parameters with sufficient precision.
