It is not seen in silicon devices. Reed and Tour are confident that they will be able to achieve even larger switching responses at room temperature and above. Eventually, Reed says, a single molecule could be used as an electronic switching device. Such a molecule would be a million times smaller than one of today's transistors, the switching devices of silicon electronics. So molecule-based devices would be much smaller than transistors and cheaper to fabricate, Tour points out.
Researchers also have high hopes for nanotube-based electronics.
Carbon nanotubes, which can be metallic or semiconducting, have already been shown to function as electronic devices. Now the Delft team, led by Cees Dekker, a professor of applied physics, has shown that a kink, or bend, in the nanotube modifies the tube's electronic properties, as predicted. Dekker's team, including postdoc Zhen Yao, measured the electrical behavior of individual kinked nanotubes lying across an electrode array on a flat surface. The researchers believe these particular kinks are due to the presence of a pentagon and a heptagon on opposite sides of the otherwise hexagonal carbon lattice. In one case, where the kink seamlessly fused a metallic nanotube segment with a semiconducting one, the kink acted like a rectifying diode, passing current in only one direction.