Researchers say they have fabricated ultra-small wires out of materials that could previously never be used together. The result, they say, represents a major advance in nanotechnology research, and could move the sci-fi fantasy of ultra-small supercomputers and microscopic electronic devices closer to reality.

University of California-Berkeley chemist Peidong Yang says he made "superlattice" nanowire, a strand less than 100 nanometers in diameter, by alternating segments of silicon and silicon germanium. Yang "grew" the wire like a crystal, adding blocks of each material in turn as the structure formed.

"These are not materials you can bring together in a traditional semiconductor manufacturing environment," says Larry Bock, president and CEO of Nanosys Inc., a company he co-founded with Yang which is licensing the technology. "But when you operate down on this size scale, you don't have those surface tensions."

The result combines the best of both materials, and its composition can be customized for different functions. A nano-wire can precisely control electrical current, can emit light, can heat or cool a device, or even store information. And the tiny wires can serve as components for more complicated devices, allowing engineers to build smaller and smaller electronic and optical hardware.