A team at North Carolina State University has discovered that graphene conductivity is reduced in the presence of multi-layers.
The Carbon atoms in graphene are arranged in such a manner that its electrons can move about. Mobile electrons represent high conductivity. Team leader Dr. Marco Buongiorno-Nardelli and NC State electrical and computer engineer Dr. Ki Wook Kim, however, wanted to study the behavior of real graphene.
According to Buongiorno-Nardelli, the electrons are not alone in graphene. Also present are pollutants and vibrations caused by the atoms in the material. The electrons meet and communicate with these vibrations, impacting the conductivity. Buongiorno-Nardelli, Kim and graduate students Kostya Borysenko and Jeff Mullen simulated a computer model to foretell definite conductivity of graphene, in single and bilayer form, where two grapheme sheets were placed one on the other. A conductive material used in electronic devices needs to be turned on or off, so it is necessary that the conductive material has two layers. The optimized computers at Oak Ridge National Laboratories helped the team discover both positives and negatives of graphene.
The research paper has been published as an Editor's Suggestion in the April 15 issue of Physical Review B. A single graphene layer displayed mobility and conductivity higher than the team had anticipated. The mobility of electrons in a bilayer graphene is e lower than in a single layer.
The research was funded by the U.S. Department of Energy and the DARPA-CERA program.
Source: http://www.ncsu.edu