This news release from the University of California at Berkeley is quite astonishing. Here are the opening paragraphs.
As scientists shrink materials down to the nanometer scale, creating nanodots, nanoparticles, nanorods and nanotubes a few tens of atoms across, they've found weird and puzzling behaviors that have fired their imaginations and promised many unforeseen applications.
Now University of California, Berkeley, scientists have found another unusual effect that could have both good and bad implications for semiconductor devices once they've been shrunk to the nanometer scale.
So what did they find?
In a paper appearing in the Aug. 28 issue of Nature, a UC Berkeley team comprised of physicists, chemists and mineralogists reports on the unusual behavior of a semiconducting material, zinc sulphide (ZnS), when reduced to pieces only 3 nanometers across -- clumps containing only 700 or so atoms.
They found that when the surface of a ZnS nanoparticle gets wet, its entire crystal structure rearranges to become more ordered, closer to the structure of a bulk piece of solid ZnS.
Here is one image of the structure of a 3 nanometer zinc sulphide (ZnS) nanoparticle without water bound to the surface (Credit: Jillian F. Banfield, Division of Ecosystem Sciences, UC Berkeley).
Here is now the structure of the same nanoparticle with surface-bound water. (Credit: Id.)
How can this be used for? Surprisingly, they think that it "could provide a way to tell whether pieces of rock from outer space came from planets with water."
Hengzhong Zhang, a research scientist and physical chemist, said these effects could have implications for our understanding of extraterrestrial materials and identification of extraterrestrial rocks, especially when the interpretation is being done by a robotic probe. A nanoparticle that formed in a place with water, such as Earth, would have a more ordered surface than a nanoparticle formed in space, where water is not present.
"Nanoparticles are probably widespread in the cosmos, and their surface environments may vary significantly, such as water versus no water, or the presence of organic molecules," said Jillian Banfield, professor of earth and planetary science at UC Berkeley.
For more technical information, please the original story.
Source: University of California at Berkeley News release, August 27, 2003
12:27:34 PM
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