Nanorods go for the gold

To streamline fabrication of future nanoscale electronic circuitry, researchers are investigating ways to dust a surface with tiny semiconductor specks that would arrange themselves into wires and transistors. As a step toward that goal, Israeli researchers have now created building blocks with attachments that can lead to desired patterns.

NANODUMBBELL. A false-color electron micrograph shows a tiny semiconductor rod with gold blobs at each end. Such blobs can serve as electrical contacts or chemical docking points for this roughly 30-nanometer-long structure. E. Rothenberg/Hebrew Univ. of Jerusalem

For years, nanotechnologists have grown spherical and rod-shaped crystals of semiconductors only a few nanometers across. Such nanocrystals have shown promise in a variety of optical and electronic applications, such as microlasers, solar cells, and biomedical markers (SN: 3/6/04, p. 157: Available to subscribers at Quantum sentinels).

By adding a gold compound to a solution in which nanorods of the semiconductor cadmium selenide are growing, a team at the Hebrew University of Jerusalem led by Uri Banin has created semiconductor cylinders tipped with gold beads. Those beads provide an electric connection to the rods, Banin says. They can also serve as attachment points for chemicals that guide nanorod self-assembly into specific arrangements. The team describes its “nanodumbbells” in the June 18 Science.

More Stories from Foogue on Tech