the combination of minuscule electrical and mechanical components in a single device less than 1 mm across, such as a valve or a motor. Although micromechanical production processes and applications are still in the developmental stage, efforts have begun to develop machines?called micromachines or micromechanisms?1,000 times smaller. Nanotechnology
is concerned with atomic- and molecular-scale devices. Such devices can be constructed using a scanning tunneling microscope
. A single atom has been used as an electrical switch and an individual molecule used to convert alternating current into direct current. Cluster chemistry has produced small balls and tubes (see fullerene
) containing between 10 and 1,000 atoms that may be useful in forming nano-thin wires and transistors
that operate on just a few electrons. A third nanotechnological approach is to grow such devices from proteins, DNA, or synthesized organic molecules. Nanotechnologies are still in the laboratory stage, but practical applications are envisioned in such diverse areas as computers, pharmaceuticals, and metrology. For example, American chemist George M. Whitesides has used hydrocarbon molecules, called alkanethiols, that are self-assembling (i.e., arrange themselves into ordered, functioning entities without human intervention, as do living cells) to form ordered rows on a gold surface; such a process could be used to produce much thinner lines on an integrated circuit than can be accomplished using conventional techniques.
See K. E. Drexler and C. Peterson, with G. Pergamit, Unbounding the Future: The Nanotechnology Revolution (1991); A. J. Bard, Integrated Chemical Systems: A Chemical Approach to Nanotechnology (1994); E. Regis, Nano: The Emerging Science of Nanotechnology (1995).
The Columbia Electronic Encyclopedia, 6th ed. Copyright 2012, Columbia University Press. All rights reserved.
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