Eur. Phys. J. B (2013) 86: 182
https://doi.org/10.1140/epjb/e2013-30771-6

Regular Article

Amplification of terahertz radiation in carbon nanotubes

¹ Department of Physics, Laser and Fibre Optics Centre, University of Cape Coast, Cape Coast, Ghana
² Department of Physics, The Pennsylvania State University, Altoona College, Altoona, Pennsylvania 16601, USA
³ Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
⁴ National Centre for Mathematical Sciences, Ghana Atomic Energy commission, Kwabenya, Accra, Ghana
⁵ Department of Mathematics, University of Cape Coast, Cape Coast, Ghana
⁶ Department of Applied Physics, University for Development Studies, Navorongo, Ghana

^a e-mail: cxa269@psu.edu

Received: 22 August 2012
Received in final form: 1 January 2013
Published online: 24 April 2013

Abstract

We investigate theoretically the feasibility of amplification of terahertz radiation in aligned achiral carbon nanotubes, a zigzag (12,0) and an armchair (10,10) in comparison with a superlattice using a combination of a constant direct current (dc) and a high-frequency alternate current (ac) electric fields. The electric current density expression is derived using the semiclassical Boltzmann transport equation with a constant relaxation time. The electric field is applied along the nanotube axis. Analysis of the current density versus electric field characteristics reveals a negative differential conductivity behavior at high frequency, as well as photon assisted peaks. The photon assisted peaks are about an order of magnitude higher in the carbon nanotubes compared to the superlattice. These strong phenomena in carbon nanotubes can be used to obtain domainless amplification of terahertz radiation at room temperature.