Nano revolution

All over the world, interdisciplinary teams are uncovering new engineering truths to support the statement made in 1959 by US physicist Richard Feynman that "the principles of physics do not speak against the possibility of manoeuvring things atom by atom". Nanotechnology is based on the ability to create and manipulate materials, devices and systems at the nanometre scale; that is, one billionth of a metre (10/sup -9/). Another definition comes from considering nature's art of 'building up', by self-assembling atoms and molecules into useful structures. This proves particularly useful in the field of semiconductors, where designers are running out of things they can do with traditional lithographic techniques. Typically, semiconductor devices are grown from silicon on top of which various materials are deposited and then etched away until the needed circuit remains. But photolithography is reaching its physical limits, since etching features smaller than the wavelength of light becomes increasingly challenging. Hence the interest in building up, instead of etching down.