We’ve come a long way from the first glass-and-light optical microscopes. These days, scientists can focus on individual molecules using advanced methods like atomic force microscopy (AFM), where a miniscule probe feels out the details of a surface. And in this AFM image of a nanographene molecule, the resolution is so high that for the first time, we can see the individual bonds between atoms, shown here as green lines.
In a new paper in the journal Science, IBM researchers used the same imaging technique to measure the length and relative strength of individual bonds in the spherical carbon molecules called buckyballs. Their method can not only improve our intimate understanding of these and other molecules—it also lets us get up close and personal with the building blocks of all matter.
Image courtesy of IBM Research – Zurich / Flickr
The graphene filled in the smaller hole with fresh
Due to their extraordinary abilities, graphene and other one-atom-thick molecules like carbon nanotubes have enormous potential for use in fields from electronics to medicine. For example, graphene is physically strong, transparent, flexible, and a great conductor of both electricity and heat—and now the two-dimensional carbon molecule can add another power to its roster: self-healing. When researchers made holes in a graphene sheet, the molecule rebuilt its own structure using new carbon atoms. This ability might help researchers grow graphene in large quantities and specific shapes.
This picture may look like an exuberant patchwork quilt, or a stretch of really interesting farmland as seen from an airplane. In fact, what you’re looking at is sheet of graphene–a one-atom-thick layer of carbon, measuring about 100,000 atoms across.
The image, produced by an electron microscope, reveals that the honeycomb-like lattice of carbon atoms that forms a sheet of graphene is full of irregularities. Each sheet is composed of patches of atoms, and each patch has a slightly different rotation than that of its neighbors. By firing electrons at a sheet and using different colors to identify the angles at which the electrons bounced back, researchers made this rainbow image of a graphene sheet with the patch boundaries clearly shown.
Lead researcher David Muller says this is an easy and efficient way to understand a graphene sheet’s properties.
“You don’t want to look at the whole quilt by counting each thread. You want to stand back and see what it looks like on the bed. And so we developed a method that filters out the crystal information in a way that you don’t have to count every atom,” said David Muller, professor of applied and engineering physics and co-director of the Kavli Institute at Cornell for Nanoscale Science. [press release]
The research, which was published in Nature, will be useful as nanotechnologists continue to investigate graphene’s exciting electrical properties. Researchers had previously thought that larger patches would improve the electrical conductivity of graphene, but Muller’s experiments suggest that theory is wrong. Rather, it’s impurities in graphene sheets that interfere with their conductivity, he argues.
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Image: Cornell University/ P.Y. Huang / D. A. Muller
The wonder material snagged the 2010 Nobel Prize in Physics today, bringing the award to Russian scientists Andre Geim and Konstantin Novoselov who work at the University of Manchester in the U.K.
Novoselov and Geim didn’t discover graphene, which is made of sheets of carbon just one atom thick. Physicists had known about it for years, but these two showed the way to produce it quickly and easily.
Novoselov was a postdoctoral fellow working in Geim’s lab in 2004 when the researchers discovered that they could make atomically thin slabs of carbon by repeatedly cleaving graphite—essentially pencil lead—with adhesive tape. Their 2004 Science paper describing the material and its the electrical properties has already been cited more than 3,000 times, according to Thomson Web of Science. [Scientific American]
100 gigahertz of processing power—not bad for a single sheet of atoms.
In a paper in Science, researchers at IBM say they have created the fastest-ever graphene transistor, with a cut-off frequency (the highest it can go without significant signal degradation) that at 100 GHz is nearly four times higher than their previous attempt. Similar silicon-based transistors have only been able to reach a turtle-like clock rate of about 40 GHz, or 40 billion cycles per second.