ScienceDaily (Nov. 19, 2009) — The performance of modern electronics increases steadily on a fast pace thanks to the ongoing miniaturization of the utilized components. However, severe problems arise due to quantum-mechanical phenomena when conventional structures are simply made smaller and reach the nanometer scale. Therefore current research focuses on the so-called bottom-up approach: the engineering of functional structures with the smallest possible building blocks — single atoms and molecules.

Electron current through two C60-molecules which are contacted with electrodes. As they are only one billionth of a meter in diameter, ultra high precision is needed in order to control their distance. (Credit: Copyright CAU)

For the first time a collaboration of researchers across Europe now achieved to investigate the electrical behaviour of only two C60 molecules touching each other. The molecule which is shaped like a football was discovered in 1985 and since then has attracted tremendous attention by researchers all over the world due to its unique chemistry and potential technological applications in nanotechnology, materials science and electronics.

The findings of the researchers from institutes in Germany, France, Spain and Denmark were published in a recent issue of Physical Review Letters. A scanning tunnelling microscope (STM) was used to construct an ultra small electrical circuit comprised of only two C60 molecules, each just 1 nanometer in diameter. The researchers first picked up a single C60 molecule with the STM tip and thereafter approached a second molecule with a precision of a few trillionths of meters. During this controlled approach the physicists were able to measure the electrical current that flows between the two molecules. Understanding this current, which depends critically on the distance between the molecules, is important for utilizing molecules in future electronics.

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