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Affiliations: |
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Nanophysics | |||||||||
We are interested in the high frequency properties and physics of nanostructured materials. Carbon nanotubes and graphene have interesting electrodynamic properties that are governed by quantum mechanics. We have discovered that carbon nanotube (CNT) thin films can act as transparent conductors. They can be thin enough to be optically transparent, yet still shield out RF and microwave fields quite effectively. For example, shielding effectiveness of 43 dB at 10 MHz and 28 dB at 10 GHz is found for films with 90% optical transmittance. We have also investigated the high frequency conductivity and nonlinear resistance properties of CNT networks and established a novel connection between these measurements. They both measure the mean distance between high-resistance contacts between the nanotubes. In collaboration with Prof. Michael Fuhrer, we are examining the use of single carbon nanotubes as Schottky detectors of microwave and millimeter wave radiation. We have quantitatively measured the reflectivity of few-layer graphene to distinguish between 1-layer, 2-layer and 3-layer regions of the material. This work is done in collaboration with Prof. George Gruner of UCLA and Prof. Michael Fuhrer of CNAM/UMD. Papers: (Papers can also be downloaded from the full publication list) 122. Hua Xu, Liangbing Hu, Steven M. Anlage, and George Gruner, “Microwave shielding of transparent and conducting single-walled carbon nanotube films,” Appl. Phys. Lett., 90 , 183119 (2007). pdf 125. Hua Xu, Shixiong Zhang, Steven M. Anlage, Liangbing Hu, and George Grüner, “ Frequency- and electric-field-dependent conductivity of single-walled carbon nanotube networks of varying density ,” Phys. Rev. B 77 , 075418 (2008). DOI: 10.1103/PhysRevB.77.075418. pdf E. Cobas, M. S. Fuhrer, “Microwave rectification by a carbon nanotube Schottky diode,” Appl. Phys. Lett. 93, 043120 (2008). DOI: 10.1063/1.2939095. pdf Enrique D. Cobas, Steven M. Anlage, and M. S. Fuhrer, “Single Carbon Nanotube Schottky Diode Microwave Rectifiers,” IEEE Trans. Microwave Theory Tech. (Special Issue on Radio-Frequency Nanoelectronics) 59, 2726-2732 (2011). pdf Behnood G. Ghamsari, Jacob Tosado, Mahito Yamamoto, Michael S. Fuhrer, Steven M. Anlage, “Determination of the Optical Index for Few-Layer Graphene by Reflectivity Spectroscopy,” arXiv:1210.0575. pdf |
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Center for Nanophysics and Advanced Materials,
University of Maryland, College Park, MD 20742-4111
Phone: (301) 405-7321 Fax: (301) 405-3779 Copyright © 2008 University of Maryland Contact us with comments, questions and feedback |