OAK RIDGE, Tenn., Oct. 7, 1996 --Thanks to a problem with a high-tech microscope, researchers at the Department of Energy's (DOE) Oak Ridge National Laboratory (ORNL) have developed microscopic sensors. These hairlike, silicon-based devices are at least 1,000 times more sensitive and 1,000 times smaller than currently used sensors. Each microsensor spans the width of a human hair.
They can detect and measure relative humidity, temperature, pressure, flow, viscosity, sound, natural gas, mercury vapor, and ultraviolet and infrared radiation. They show potential as biosensors Microcantilevers of silicon or silicon nitride have been made that are smaller than this period. These "microscopic diving boards" project from miniature chips about the size of a grain of rice. For this innovation of microminiature sensors, ORNL developers Thundat, Eric Wachter, Mitch Doktycz, Rick Oden, and Bruce Warmack, all in HSRD, were elected to the International Hall of Fame of the Inventors Clubs of America. ORNL's microcantilever sensor technology received an R&D 100 Award from R&D Magazine. The awards recognize the year's most significant technological innovations. "We showed that a microcantilever would bend in a measurable way if its tip is coated with a material that attracts another material from the air," Warmack says, "For example, a gold-coated cantilever absorbs mercury vapor, which stiffens the cantilever, causing it to bend and changing the way it vibrates. A gelatin tip absorbs water, measuring humidity." "These sensors can also respond sensitively to heat," Thundat says. "A silicon microcantilever coated with aluminum bends more with rising temperature because aluminum expands more than silicon. Such a device can measure temperature and even detect infrared radiation and heat-generating chemical reactions." When set in motion, microcantilevers have a natural vibration that changes in the presence of sound waves or a fluid (enabling measurements of viscosity and pressure). Changes in cantilever position or vibration rate can be detected by measuring wobble in reflected laser beams. "Future silicon devices," Warmack says, "will probably be based on piezoresistance ORNL, one of the Department of Energy's multiprogram national research and development facilities, is managed by Lockheed Martin Energy Research. (Photo of Thomas Thundat with microminiature sensor available on request) NOTES TO EDITORS: If you would prefer to receive your press releases by e-mail, please send your e-mail address to culverjw@ornl.gov You may read other press releases from Oak Ridge National Laboratory or learn more about the Lab if you have access to the Internet. You can find our information on the World Wide Web at http://www.ornl.gov
Written by Carolyn Krause
Microcantilevers of silicon or silicon nitride have been made that are smaller than this period. These "microscopic diving boards" project from miniature chips about the size of a grain of rice. For this innovation of microminiature sensors, ORNL developers Thundat, Eric Wachter, Mitch Doktycz, Rick Oden, and Bruce Warmack, all in HSRD, were elected to the International Hall of Fame of the Inventors Clubs of America. ORNL's microcantilever sensor technology received an R&D 100 Award from R&D Magazine. The awards recognize the year's most significant technological innovations.
"We showed that a microcantilever would bend in a measurable way if its tip is coated with a material that attracts another material from the air," Warmack says, "For example, a gold-coated cantilever absorbs mercury vapor, which stiffens the cantilever, causing it to bend and changing the way it vibrates. A gelatin tip absorbs water, measuring humidity."
"These sensors can also respond sensitively to heat," Thundat says. "A silicon microcantilever coated with aluminum bends more with rising temperature because aluminum expands more than silicon. Such a device can measure temperature and even detect infrared radiation and heat-generating chemical reactions."
When set in motion, microcantilevers have a natural vibration that changes in the presence of sound waves or a fluid (enabling measurements of viscosity and pressure).
Changes in cantilever position or vibration rate can be detected by measuring wobble in reflected laser beams. "Future silicon devices," Warmack says, "will probably be based on piezoresistance ORNL, one of the Department of Energy's multiprogram national research and development facilities, is managed by Lockheed Martin Energy Research. (Photo of Thomas Thundat with microminiature sensor available on request) NOTES TO EDITORS: If you would prefer to receive your press releases by e-mail, please send your e-mail address to culverjw@ornl.gov You may read other press releases from Oak Ridge National Laboratory or learn more about the Lab if you have access to the Internet. You can find our information on the World Wide Web at http://www.ornl.gov
Written by Carolyn Krause
ORNL, one of the Department of Energy's multiprogram national research and development facilities, is managed by Lockheed Martin Energy Research.
(Photo of Thomas Thundat with microminiature sensor available on request)
NOTES TO EDITORS:
If you would prefer to receive your press releases by e-mail, please send your e-mail address to culverjw@ornl.gov
You may read other press releases from Oak Ridge National Laboratory or learn more about the Lab if you have access to the Internet. You can find our information on the World Wide Web at http://www.ornl.gov
Written by Carolyn Krause