Background Essay: Nanowires and the Ever-Shrinking Microchip

Yesterday’s room-sized supercomputers are today’s miniature microchips. Today’s smaller devices are more portable, cost less to make, consume less power, and have longer-lasting batteries. But how small can we go? How much power and performance can we squeeze out of ever-shrinking microchips?

A nanometer is one-billionth of a meter, which is thousands of times smaller than the width of a human hair. The nanochip does not yet exist, but materials scientists and engineers are steadily advancing toward nanocomputing. Creating materials at that scale raises unique challenges – electrons that jump their wires, circuits that overheat, and the need for super-tiny tools and innovative manufacturing techniques to create nanoscale objects.

The components of today’s electronics are measured on the macroscale (visible to the naked eye) and microscopic (visible using a microscope) scale. But to push the limits of “smaller”, materials scientists are investigating how to build and work on the nanoscale (one billionth of a meter). Nanoscale objects are billions of times smaller than everyday objects measured on the macroscale.

Nanotechnology involves engineering new materials out of individual atoms and molecules. When you build things on such a small scale, things act differently than our on scale. One area of nanotechnology is the development of nanowires, which are wires thinner than 100 nanometers in diameter. Nanowires are so thin compared to their length that they are considered to be one-dimensional objects.

They can be made from metals, such as titanium or molybdenum, or non-metals, such as silica, which is the most common component of sand. One way nanowires are made is by dragging a thicker wire through a very hot flame using the tip of a tiny probe to thin it. They can also be made “from scratch” by combining atoms using several common laboratory techniques.

Materials scientists are designing some nanowires that conduct light instead of electrons, which will eliminate the problems with overheating circuits. Replacing silicon with a newly discovered form of carbon called graphene, which is a single-atom thick layer of carbon, may make possible new computer chips that allow electrons to move 1,000 times faster, making computers even more powerful.

The promise of nanotechnology goes beyond smaller, more powerful computers. Picture a TV screen that’s a flexible film that you could roll up and put in your pocket. Or e-paper embedded with invisible nanowires that has the appearance of natural paper but is digital. Or new medical procedures to remove tumors without surgery or deliver medicine only where it is needed.