Monday, June 06, 2005

"CHIPS: Organic molecule switches like a transistor"

Researchers at the University of Alberta have successfully demonstrated a single-molecule switch and transistor. "There is no longer a question of whether a single molecule can be used as a switch; we have shown that it can be done," professor Robert Wolkow said. "Also, we have demonstrated how you can get two electrodes to act like the three electrodes normally associated with a transistor. In particular, we have shown that a chargeable atom can act as a gate using the same electrode that is also acting as the source." But there's a caveat: "We don't yet have any kind of realistic temporal control" of the switch," Wolkow said. "Right now, it takes minutes to turn it on and off." Working with postdoctoral fellows Paul Piva and Stanislav Dogel, as well as graduate student Janik Zikovsky, Wolkow's team placed a single organic molecule on a silicon substrate so that the molecule acted as the transistor channel, with the substrate acting as a back gate for switching. The work was performed in cooperation with staff scientists and their postdoctoral assistants at the National Institute for Nanotechnology, which is a part of the National Research Council of Canada, as well as with professor Werner Hofer of the Surface Science Research Centre at Britain's University of Liverpool. Wolkow's group has been working with many organic molecules, learning how to bond them to silicon substrates and get them to line up into rows. But the current demonstration is the first to inject electrons into the molecule.