Terahertz time-domain detection of ballistic electron resonance in a single-walled carbon nanotube

PHYS 668

Zhaohui Zhong, zzhong@ccmr.cornell.edu, Center for Nanoscale Systems, Cornell University, Ithaca, NY 14853, Nathaniel Gabor, Laboratory of Atomic and Solid-State Physics, Cornell University, Ithaca, NY 14853, Jay E. Sharping, jsharping@ucmerced.edu, School of Natural Sciences, University of California at Merced, Merced, CA 95344, Alexander L. Gaeta, a.gaeta@cornell.edu, School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, and Paul L. McEuen, mceuen@ccmr.cornell.edu, Laboratory of Atomic and Solid State Physics, Cornell University, 510 Clark Hall, Cornell University, Ithaca, NY 14853.
Understanding the terahertz (~ 100 GHz to 10 THz) electrical properties of nanomaterials is of relevance both to the fundamental physics of low-dimensional electron transport and to the operation of next-generation smaller and faster electronics. We perform the first time-domain terahertz electrical measurements of a prototypical nanoscale device: a single-walled carbon nanotube transistor. By integrating a terahertz source and a carbon nanotube transistor on the same substrate, high frequency signals are generated locally by the source and detected locally by the nanotube transistor. Significantly, a ballistic electron resonance is directly observed with a picosecond-scale period corresponding to the roundtrip transit of an electron along the nanotube. The electron velocity is measured to be constant and equal to the Fermi velocity, showing that the single-particle excitations of the nanotube instead of the plasmon mode dominate the high frequency response. These results demonstrate a powerful new tool for directly probing picosecond electron motion in nanostructures. Further, they show that carbon nanotubes, with their constant Fermi velocity, are uniquely suited for creating micron-scale terahertz resonators.
 

Nanostructured Materials
8:20 AM-12:00 PM, Thursday, April 10, 2008 Morial Convention Center -- Rm. 338/339, Oral

Division of Physical Chemistry

The 235th ACS National Meeting, New Orleans, LA, April 6-10, 2008