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5 December 2013 11:26 am ,
Vol. 342 ,
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
Snake venoms are remarkably complex mixtures that can stun or kill prey within minutes. But more and more researchers...
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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New Carbon Shines Bright
29 October 1998 6:30 pm
Scientists have created a sparkling form of carbon that can scatter light like opal. The relatively simple technique for making the carbon, described in tomorrow's Science, may provide an easier way to make structures that can process light signals. Scientists hope that carbon may make a more efficient band-gap material--a material that excludes light of certain wavelengths and is therefore the photonic counterpart of a semiconductor--in future optoelectronics applications.
To create a new carbon structure with this ability, an international team tried mimicking opal, which consists of tightly packed silica spheres. Because these spheres are the size of light waves, they diffract light in rainbow colors.
As a template, the team used artificial opals made of silica spheres ranging in diameter from 150 to 300 nanometers. They infiltrated the faux opal with a phenolic resin that filled the empty space between the spheres. Then they dissolved the silica spheres with hydrofluoric acid, leaving just the newly built phenol resin walls, which were transformed into a pure carbon structure by heating up to 1000oC. "We were very surprised that this process that we developed actually works to make beautifully opalescent materials," says team leader Ray Baughman of AlliedSignal Inc. in Morristown, New Jersey. Because the basic elements of this spongelike structure are cubic, they christened the material "cubic-graphite."
The scientists used "a very clever method" to create the new material, says Eli Yablonovitch of the University of California, Los Angeles. The method will really be fruitful if it can be used to make photonic structures out of other materials, such as metals, oxides, and ceramics that may have even better properties, such as not conducting electricity or absorbing light. The obtained structure is "a very promising system.... It is likely to be very successful" for applications in optoelectronics.