Month: March 2001

from the STM-nano-fabrication dept.

John Faith points out an article in EE Times in which Japanese nanotechnology research scientist Masakazu Aono, head of the surface and interface laboratory at Japan's Institute of Physical and Chemical Research, claims his team is now only months away from developing Japan's first single-electron tunneling transistor capable of operating at room temperature ("Researchers close in on single-atom switch," by P.Kallender, 7 March 2001).

The transistor Aono is developing consists of three, 3-nanometer-wide "wires" that act as a source and a drain, each separated from a well containing a 10-atom-diameter cluster of 500 silver atoms that acts as a capacitor. On the other side of the separation lies the gate, which sits 4 nm from the capacitor, with the whole unit resting on a graphite substrate. The circuit works by exploiting the difference in the quantum conductance potentials created between the source drain and the capacitor. When carrying a single electron, current can flow through source and drain, said Aono, but 1 volt placed at the gate adds a second electron to the capacitor, thus raising its potential and closing the circuit.
"We can make an atomic switch in a cluster of silver atoms," he said. "The island is so small we are talking about a one-electron effect circuit."

Read more for additional details . . .

from the One-dimensional-nanotechnology dept.

SaturnFX calls our attention to an interesting Georgia Tech press release on Science Daily. According to the release, researchers at the Center for Nanoscience and Nanotechnology have created a new class of nanometer-scale structure that could be the basis for inexpensive ultra-small sensors, flat-panel display components and other electronic nanodevices. The researchers claim these extremely thin and flat structures — made of semiconducting metal oxides and dubbed "nanobelts" — offer significant advantages over the nanowires and carbon nanotubes.

The ribbon-like nanobelts are chemically pure, structurally uniform and largely defect-free, with clean surfaces not requiring protection against oxidation. Each is made up of a single crystal with specific surface planes and shape. Typical width of the nanobelts is from 30 to 300 nanometers, with a thickness of 10-15 nanometers. Some have been produced in lengths of up to a few millimeters, though most are tens to hundreds of micrometers long. The work is described in the March 9 issue of Science.

"Current research in one-dimensional systems has largely been dominated by carbon nanotubes," said Zhong Lin Wang, professor of Materials Science and Engineering and director of the Center for Nanoscience and Nanotechnology at the Georgia Institute of Technology. "It is now time to explore other one-dimensional systems that may have important applications for nanoscale functional and smart materials. These nanobelts are the next step in developing structures that may be useful in wider applications."

The press release also appears on the Georgia Tech web site, with a link to images. The research was sponsored by Georgia Tech, and a provision patent application has been filed on the new structures.

from the "using-foresight-to-protect-the-environmental-future" dept.

The US Environmental Protection Agency is inviting applications for "Exploratory Research to Anticipate Future Environmental Issues" covering:

1. Exploratory Research in Nanotechnogy
2. Futures Research in Natural Sciences
3. Futures Research in Socio-Economics

The nanotech part encourages a range of MNT-type ideas, natural science futures hopes for novel solutions, while the socio-economic part requests fairly conventional trend analysis. Closing date for the Nanotechnogy Program ($5m available) is June 18, 2001. Read More for a quote from the nanotech RFA.

from the redefining-"fluid" dept.
A Georgia Tech press release at EurekAlert describes work by Feynman Prizewinner Uzi Landman: "Landman's research group has reported on the tendency of lubricant molecules such as hexadecane and other molecular fluids to form highly ordered layers in planes parallel to the motion of the confining surfaces. On size scales that approximate multiples of the molecular width, these layered lubricants appear to increase their viscosity, 'becoming, at equilibrium and at various stages of the sliding motion, liquid-like in the plane parallel to the sliding surfaces and solid-like in the direction perpendicular to the surfaces,' Landman said…'We must find clever ways to harness and control these new behaviors in order to realize the opportunities in nanotechnology." " CP: While we do need to know about fluids at nanoscales, do nanomachines need "lubrication" per se?