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3I304 Chen Li

Where world is calculated and observed under one billionth of a meter

There are several important modern developments. The atomic force microscope (AFM) and the Scanning Tunneling Microscope (STM) are two early versions of scanning probes that launched nanotechnology.

Tools

Typical AFM setup

the scanning acoustic microscope (SAM) developed by Calvin Quate and coworkers in the 1970s made it possible to see structures at the nanoscale.

Tools

KSI SAM-2000 Scanning Acoustic Microscope

Nanomaterials is a field which takes a materials science-based approach to nanotechnology. It studies materials with morphological features on the nanoscale.

Nanomaterials

Carbon

Diamond is one allotrope of carbon. In the diamond structure, each carbon atom is covalently bonded to four others and has a tetrahedral geometry.

Carbon

Carbon

In 1998, Chinese scientists successfully converted the carbon tetrachloride into carbon nanopowder, which is much harder than normal carbon. In other words, that was diamond. This is rewarded as” Turn the straw into gold”

Solar Energy Conversion

Solar Energy Conversion

The problem with solar energy is that it has not been inexpensive enough in the past. A new type of nanoparticle -- a tiny chemical compound far too small to be seen with the naked eye -- that may reap big dividends in solar power.

"You can make dramatically different colors just by changing the size of the nanoparticles." said David Kelley, professor of chemistry at Kansas State University.

Solar Energy ConversionToday's solar panels are made with silicon. The silicon usually has impurities, which limits its efficiency. Purifying a chemical is too expensive. For that reason, smaller is better.

Kelley is developing nanoparticles that are just the right size for solar cells -- they can absorb all visible light but nothing from the invisible light at the red end of the spectrum, which would reduce voltage. "The correct-sized nanoparticles look dark red to black. There is an optimum size and that's what you want to shoot for," Kelley said. -ScienceDaily (Aug. 9, 2002)

Solar Energy Conversion

Semiconductor Devices

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. -ScienceDaily (Aug. 28, 2003)

Semiconductor Devices

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.

Semiconductor Devices

Gilbert and co-author Hengzhong Zhang, a research scientist and physical chemist, suggest that many types of nanoparticles may be as sensitive to water as ZnS.

Semiconductor Devices

We think that, for some systems of small nanoparticles maybe 2 to 3 nanometers across, this kind of structural transition may be common," Zhang said.

"There's a good and bad side to this," Gilbert added. "If we can control the structure of a nanoparticle through its surface, we can expect to produce a range of structures depending on what molecule is bound to the surface. But this also produces unexpected effects researchers may not want."

References

http://en.wikipedia.org/wiki/Nanomaterials

http://en.wikipedia.org/wiki/Nanotechnology

http://www.uncp.edu/home/mcclurem/ptable/carbon.htm

http://www.sciencedaily.com/releases/2002/08/020809071535.htm

http://www.sciencedaily.com/releases/2003/08/030828071948.htm