As a step to molecular circuits, researchers would like to control the charge flowing across single organic molecules, thereby turning them into electrical junctions. But the relatively enormous electrodes abutting the molecules typically complicate such attempts. Leaving a single “dangling bond,” or unpaired electron, on a silicon electrode may be the key to precise charge control of adjacent molecules, reports a group from the University of Alberta in Canada. They deposited lines of ringed carbon molecules on a silicon surface in such a way that a dangling bond punctuated the end of each line. A scanning tunneling microscope played over the structures felt more charge in carbon molecules closer to dangling bonds, indicating that the bonds could serve to precisely alter a molecule's conductivity. See the June 2 Nature for details.
This article was originally published with the title "The Next Little Thing" in Scientific American 293, 2, 28 (August 2005)