The building blocks of future electronic components may be only a billionth of a meter wide and made of the same stuff that's in a pencil--but super strong, incredibly flexible, and with nearly unlimited potential applications. These structures, called nanotubes, could lead to innovations ranging from high-speed microscopic circuitry to ultrafast optical filters.
Nanotubes are usually made of a sheet of graphite (itself a strong latticework of carbon molecules) rolled into a long, thin cylinder. That shape makes them strong and flexible and gives them numerous electrical and mechanical properties that have wowed scientists since their discovery by Japanese researcher Sumio Iijima in 1991. "You can use them as a conductor, an insulator, or a semiconductor, depending on how you make them," says Joseph Chiang, a professor of chemistry at the State University of New York at Oneonta. "They're very versatile."
Some scientists have investigated ways to use nanotubes as semiconductors to make super-small, ultrafast circuits. "You can make all sorts of electronic devices, like a microprocessor," Chiang says. "Integrated circuits made from nanotubes would be really tiny, really high speed, and would be almost error-free. There are no problems with heating or hot weather."
It's hard to guess when nanotubes will move from the laboratory into commercial production, Chiang says, but we could see products on the market in the next five years.
Qing Jiang of the University of California at Riverside and Quanshui Zheng of Tsinghua University in Beijing have found a way to make ultrafast oscillators, components that generate an alternating current and are vital in all kinds of devices. Using one nanotube nestled inside another, similar to the Russian Matryoshka dolls, they found they could yank out the inner sleeve, and it would automatically retract and bounce back out the other end. Because there's next to no friction between the tubes, they can oscillate billions of times a second. That could lead to revolutionary new devices in everything from fiber-optic systems to computer displays.
The tubes have applications outside of electronics. Doctors may one day use the hollow cylinders for drug delivery or for biopsies. "You can make a very small nanotube and insert it through the skin," Chiang says. There's even evidence that nanotubes made of amino acids could serve as highly effective antibiotics, poking holes in the sides of bacteria.