Scientists at the University of Manchester, in the UK, have discovered a new class of materials which are one atom thick and exhibit properties previously never thought possible. With these new materials, they are promising us a 'new industrial revolution.' Not only these new materials are ultra-thin, but they can also be ultra-strong, highly-insulating or highly-conductive. Apparently, this new class of materials has been validated by the scientific community, and even if some applications are probably decades away, you can expect to see 'ultra-fast transistors, micromechanical devices and nano-sensors based on the discovered one-atom-thick crystals already in a few years time.' Read more...
Here is the introduction of the news release from the University of Manchester.
Scientists at The University of Manchester have discovered a new class of materials which have previously only existed in science fiction films and books.
A team of British and Russian scientists led by Professor Andre Geim, [director of the Manchester Centre for Mesoscience and Nanotechnology,] have discovered a whole family of previously unknown materials, which are one atom thick and exhibit properties which scientists had never thought possible.
After this press release lingo, let's move -- gradually -- to some more technical details.
The materials have been created by extracting individual atomic planes from conventional bulk crystals by using a technique called 'micromechanical cleavage'. Depending on a parent crystal, their one-atom-thick counterparts can be metals, semiconductors, insulators, magnets, etc. Previously, it was thought that such thin materials could not exist in principle, but the research team have, for the first time, demonstrated that they are not only possible but fairly easy to make.
Below are some pictures of these very small two dimensional crystals (Credit for images and legend: University of Manchester).
[Here you can see] single-layer crystallites of (a) NbSe2, (b) graphite, (c) Bi2Sr2CaCu2Ox and (d) MoS2 visualized by AFM (a,b), SEM (c) and in an optical microscope (d). All scale bars are 1µm.
Dr Kostya Novoselov, a key investigator in this research, added: "Probably the most important part is that our discovery is not limited to just one or two new materials. It is a whole class of new materials, thousands of them. And they have a variety of properties, allowing one to choose a material most appropriate for a particular application.
This fascinating research work has been published by the Proceedings of the National Academy of Sciences (PNAS) in its July 18, 2005 issue under the name "Two-dimensional atomic crystals." Here is a link to the abstract.
We report free-standing atomic crystals that are strictly 2D and can be viewed as individual atomic planes pulled out of bulk crystals or as unrolled single-wall nanotubes. By using micromechanical cleavage, we have prepared and studied a variety of 2D crystals including single layers of boron nitride, graphite, several dichalcogenides, and complex oxides. These atomically thin sheets (essentially gigantic 2D molecules unprotected from the immediate environment) are stable under ambient conditions, exhibit high crystal quality, and are continuous on a macroscopic scale.
And here is a link to the full paper from which the above figure has been extracted. Below is the conclusion of this paper.
We have demonstrated the existence of 2D atomic crystals that can be prepared by cleavage from most strongly-layered materials. It is most unexpected if not counterintuitive that isolated 2D crystals can be stable at room temperature and in air, leaving aside the fact that they maintain macroscopic continuity and such high quality that their carrier mobilities remain almost unaffected. The found class of 2D crystals offers a wide choice of new materials parameters for possible applications and promises a wealth of new phenomena usually abundant in 2D systems. We believe that, once investigated and understood, 2D crystals can also be grown in large sizes required for industrial applications, matching the progress achieved recently for the case of single-wall nanotubes.
Finally, even if these new materials are only one atom thick, they still have three dimensions. The idea of 2D crystals and materials in our 3D world would be too disturbing. What do you think of these discoveries? Can we really talk about 'flat' materials? And will this research lead to a new industrial revolution? Please post your comments below.
Sources: University of Manchester news release, July 18, 2005; and various web sites
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