Bilayer graphene to pave way for tunable electronic devices.Byline: ANI London, June 11 (ANI): Researchers at the University of California, Berkeley The University of California, Berkeley is a public research university located in Berkeley, California, United States. Commonly referred to as UC Berkeley, Berkeley and Cal , have shown that a form of carbon called graphene has an electronic structure that can be controlled by an electrical field, a finding that may pave the way for a host of tunable electronic and photonic devices-such as transistors, LEDs and lasers. Principal author Feng Wang, UC Berkeley assistant professor of physics, claims that this is the first ever demonstration that bilayer bilayer /bi·lay·er/ (bi´la-er) a membrane consisting of two molecular layers. bi·lay·er n. A structure, such as a film or membrane, consisting of two molecular layers. graphene exhibits an electric field-induced, broadly tunable bandgap. The bandgap of a material is the energy difference between electrons residing in the two most important states of a material-valence band states and conduction band Conduction band The electronic energy band of a crystalline solid which is partially occupied by electrons. The electrons in this energy band can increase their energies by going to higher energy levels within the band when an electric field is applied to states. The bandgap determines the electrical and optical properties of the material. "The real breakthrough in materials science materials science Study of the properties of solid materials and how those properties are determined by the material's composition and structure, both macroscopic and microscopic. is that for the first time you can use an electric field to close the bandgap and open the bandgap. No other material can do this, only bilayer graphene," Nature magazine quoted Wang as saying. Tuning the bandgap of bilayer graphene can turn it from a metal into a semiconductor. Thus, a single millimeter-square sheet of bilayer graphene could potentially hold millions of differently tuned electronic devices that can be reconfigured at will. "The fundamental difference between a metal and a semiconductor is this bandgap, which allows us to create semiconducting devices," said co-author Michael Crommie, UC Berkeley professor of physics. He added: "The ability to simply put a material between two electrodes, apply an electric field and change the bandgap is a huge deal and a major advance in condensed matter physics con·densed matter physics n. See solid-state physics. condensed matter physics The scientific study of the properties of solids, liquids, and other forms of matter in which atoms or particles adhere to , because it means that in a device configuration we can change the bandgap on the fly by sending an electrical signal to the material." Graphene is a sheet of carbon atoms, each atom chemically bonded to its three neighbours to produce a hexagonal hex·ag·o·nal adj. 1. Having six sides. 2. Containing a hexagon or shaped like one. 3. Mineralogy array that looks a lot like chicken wire. And the material has been a hot topic of research, in part, because solid-state theory predicts unusual electronic properties, including a high electron mobility Electron Mobility In physics, electron mobility (or simply, mobility), is a quantity relating the drift velocity of electrons to the applied electric field across a material, according to the formula: more than 10 times that of silicon. "This is not just a technological advance, it also opens the door to some really new and potentially interesting physics," said Crommie. (ANI) Copyright 2009 Asian News International The Asian News International (ANI) agency provides multimedia news to China and 50 bureaus in India. It covers virtually all of South Asia since its foundation and presently claims, on its official website, to be the leading South Asia-wide news agency. (ANI) - All Rights Reserved. Provided by Syndigate.info an Albawaba.com company |
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