WASHINGTON, D.C. -- Although it may defy common sense, adding imperfections to materials can actually improve their performance in devices used for everything from information technology to playing music. In this special section, four articles and a special news section show how purposely creating "defects"--or putting naturally occurring defects to good use--can have major implications for the future of electronics and materials science.
The use of semiconductor devices, which allow the manipulation of electric current, has revolutionized information and communications technology. These devices are actually created by introducing impurities into specific regions of a semiconducting material, allowing researchers to control the current in a number of ways, including amplifying it or changing its direction. New applications for defects in semiconductors are being rapidly developed, but scientists do not yet have a thorough understanding of how some defects operate. While semiconductors are best known for their use in computer chips, defects also appear to be useful for improving high-speed communications technology through the engineering of a certain variety of optical fibers.
In one article, Hans J. Queisser and Eugene E. Haller review several of the major ways in which defects affect the performance of semiconductors. In some cases researchers grow pure semiconductor crystals and then "dope" them with foreign atoms. Alternatively, some defects occur naturally within a semiconductor crystal, and researchers must use their ingenuity to find ways of controlling, or even exploiting, these defects.
H. Ohno discusses advances made in merging the capabilities of
non-magnetic semiconductors, like silicon, with those of magnetic materials
(used to store massive amounts of information; for example, on hard disks). The
results could be used to engineer instruments that could perform mass storage
and process information at
Contact: Kathy Wren
American Association for the Advancement of Science