Visit the Materials360® Plus and the Materials News pages on the MRS Website for continually updated research news and features Image in Focus Pollenesian Serenity Nano Focus Tunable bandgap engineered in bilayer graphene A billion-year hard drive?
Credit: Adam Jakus, Georgia Institute of Technology
Multiple species of bare and alumina coated pollen particle images obtained via SEM.
(One of three first place winners of the the Science as Art competition at the 2009 MRS Spring Meeting. Submitted by Adam Jakus, Georgia Institute of Technology)
Graphene has no bandgap which greatly limits its uses in nanoscale electronics and photonics. Researchers have now been able to engineer a bandgap in bilayer graphene that can be precisely controlled from 0 to 250 meV. The experiment was conducted at room temperature, requiring no refrigeration of the device. Among the applications made possible by this breakthrough are new kinds of nanotransistors and – because of its narrow bandgap – nano-LEDs and other nanoscale optical devices in the infrared range.
Scientists have described a technique of placing a single nanosized iron crystal inside a hollow carbon nanotube. Like diamonds, nanotubes are among the most stable structures in existence. Once inserted into the tubes, the iron nanocrystals act as data bits, physically sliding from one end of the tube to the other in response to an electric current and in the process registering either a "1" or a "0" in the binary language of computers, forming the basis of long lasting data storage.
Materials in Focus
Polymer membrane filters arsenic from water
A new polymer membrane material has been developed that resists problems such as fouling or clogging while also screening out arsenic. The material is based on polymers, hexafluoro alcohols, that are used as a patterning material for manufacturing advanced computer chips. The researchers found that these compounds also make good water filters. The key to the membrane's performance is its pH sensitivity. At high pH, arsenic in the water becomes charged, and the fluorine groups on the polymer, which also become charged, then will repel the toxic chemical.
Thinnest superconducting metal created
A superconducting sheet of lead only two atoms thick, the thinnest superconducting metal layer ever created, has been developed by researchers. One of the innovative properties of the new sheet is that it confines the electrons to move in two dimensions, or one "quantum channel." Uniquely, the lead remains a good superconductor despite the constrained movement of the electrons through the metal.
Mineral could be evidence of naturally occurring quasicrystal
A team of researchers says it has found in a Russian mineral sample the first natural example of a quasicrystal. Numerous versions have been cooked up in the laboratory, but a natural example would indicate that nature's products are more diverse than previously thought. But the origin of such would-be minerals is a point of some contention among petrologists, since aluminum alloys do not form easily by natural processes, because the element reacts with oxygen so readily. The possibility that the quasicrystal and its related materials, including khatyrkite, are of man-made origin needs to be weighed very carefully.
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