Vol. 5 Num 1104 Mon. July 09, 2007  

Dawn of nanotechnology

Steam was the source of power for most of the machines that dominated the 19th century. Electricity and its developments played the key sole in the 20th century's technical advancement. Nanotechnology will possibly drive this new century technologically forward; to be witnessed by our children and grandchildren.

"Nano" is a term that means a billionth part. A nanometer is one billionth of a meter, a very small and practically invisible distance. It is estimated that a normal fingernail grows at the rate of about one nanometer per second! No wonder that we cannot see it growing! Hydrogen, the smallest atom, is 0.1 nanometer in diameter, and Uranium, the largest, measures 0.22 nanometer in diameter.

Today, nanotechnology governs the realm of miniaturisation. When nanotechnology is in full bloom, we will have devices and equipment that will not be visible to the naked eye! Even today it borders on the incredible, and is beyond usual comprehension.

Some idea of the scales in nanotechnology can be imagined from the following real-life comparison. A normal human hair is between 50,000 to 100,000 nanometers in diameter. Today's smallest component in a silicon chip measures around 30 nanometers across, which is 2,500 to 3,000 times thinner than an average human hair.

Earlier ideas of nanotechnology assembly conceived of tiny devices assembled atom by atom; however, its practical achievement defies definition, and borders on the absurd. It will be an extremely complicated and very slow process. Imagine building something weighing only ounces, atom by atom. The real time required for such nano-operations may well take millions of years. A self-assembly process is the realistic option, where a nano-module fits on to another nano-module; similar to a lock and key fitting each other. This analogy is applicable in biology; with trillions of cells in our body, an outside cell finds a host cell and locks onto it, and grows.

The carbon molecule is unique, because it contains many atoms of carbon with a special ability to link tightly in different patterns in the molecule! One such pattern is diamond, one of the hardest materials; another is soot or powdery graphite. The molecular patterns can be like tiny domes that are extremely strong, about a nanometer across, made of sixty carbon atoms. Scientists have discovered how to make tubes of carbon atoms into tiny cylinders that are extraordinarily strong because they are in a single molecule. Such a tube-like structure built of carbon molecules has tensile strength of over sixty times that of high-grade steel. It is possibly the strongest material that has been made.

These carbon nano-tubes have been woven like coir or hemp into a rope, invisible to the eye yet strong enough to hang a truck with! This carbon nano-tube structure is possibly the ideal material to make high-definition TV screens over twenty five square feet in area. The carbon nano-tube molecular structure has been developed with different locking combinations of carbon atoms; ushering in new, highly strong materials of construction!

Electrons literally fly across carbon nano-tubes with practically zero resistance, and these behave like superconductors. Short nano-tubes are one hundredth of the width of the finest transistor. It will be easy for these nano-chips to have ten thousand times as many switches on a two dimensional surface slightly larger than today's chip. Compared to today's chips they generate no heat, thanks to practically no resistance. Today's chips are two dimensional because of the need to dissipate the heat generated. With carbon nano-tube structure three dimensional chips will be easily possible; with massive increase in memory or logic per module. With the combination of nano-scale fabrication, super-conductivity, and three dimensional structure technologies, one can visualise the arrival of immensely powerful supercomputers that will boggle the imagination.

S.A. Mansoor is Technical Adviser, Spectra Group.