Washington, March 29 : A scientist of Indian origin has predicted that carbon nanotubes might replace the silicon chip in the future, with superconductors cited as another viable replacement.
According to Suman Datta of Pennsylvania State University, US, the silicon chip, which has supplied several decades' worth of remarkable increases in computing power and speed, looks unlikely to be capable of sustaining this pace for more than another decade.
In fact, Datta gives the conventional silicon chip no longer than four years left to run.
As silicon computer circuitry gets ever smaller in the quest to pack more components into smaller areas on a chip, eventually the miniaturized electronic devices are undermined by fundamental physical limits.
They start to become leaky, making them incapable of holding onto digital information. So, if the steady increases in computing capability that we have come to take for granted are to continue, some new technology will have to take over from silicon, according to Datta.
What Datta predicts is that the silicon chip would be replaced with carbon nanotubes in the future.
Carbon nanotubes, discovered in 1991, are tubes of pure carbon just a few nanometres wide - about the width of a typical protein molecule, and tens of thousands of times thinner than a human hair.
Because they conduct electricity, they have been proposed as ready-made molecular-scale wires for making electronic circuitry.
Some nanotubes behave as semiconductors, like silicon; others carry electric currents like metal wires. Already, fundamental elements of computer circuits such as transistors have been made from individual carbon nanotubes.
Bryan Hickey and his coworkers at Leeds have even developed a technique that will reveal an individual nanotube's structure, and then allow it to be placed in a position on a surface with an accuracy of about 100 nanometres, a fraction of the width of a human blood cell.
Other replacements for the silicon chip include superconductors, which might be used to overcome the limitations of silicon computers.
Hans Mooij of the Delft University of Technology in the Netherlands and Raymond Simmons of the National Institute of Standards and Technology in Boulder, Colorado, US, claim that superconductors - materials that conduct electricity with zero electrical resistance - can harness the power of quantum physics to boost computer power tremendously.
They attempt to improve on the power of silicon not by making components smaller but by exploiting the counterintuitive principles of quantum mechanics, the theory generally used to understand how objects behave at the scale of atoms and subatomic particles.