Self-aligning DNA wires for application in nanoelectronics

Since miniaturization in microelectronics is starting to reach physical limits, researchers seek new methods for device fabrication. One candidate is DNA origami in which strands of the biomolecule self-assemble into arbitrarily shaped nanostructures.

The formation of entire circuits, however, requires the controlled positioning of these DNA structures on a surface -- which is only possible using elaborate techniques. Researchers have come up with a simpler strategy which combines DNA origami with self-organized pattern formation.

Dr. Adrian Keller of the HZDR Institute of Ion Beam Physics and Materials Research describes the new method: "Its beauty lies with the fact that we're allowing nature to simply run its course as soon as we've created the necessary framework." In the DNA origami technique, the DNA structures self-assemble as long strands of the biomolecule fold into complex, predefined nanoscale shapes by pairing with multiple smaller DNA strands. The physicists used the technique to produce small tubes with lengths of 412 nanometers and diameters of six nanometers. These structures can be used as scaffolds for manufacturing nanoelectronic components like nanowires.

In order to align these nanotubes on the surface, the researchers drew on a principle of self-organization that is actually quite common in nature. Wind may for instance form ordered patterns on a sandy beach. "Similar processes are at work here," explains Keller. "We irradiate the surface onto which we want to place the nanostructures -- in our case, the silicon wafers -- with ions. This results in the spontaneous appearance of ordered nanopatterns resembling miniature sand dunes. At that point, our job is pretty much done as natural processes are taking over and doing all the work."