TITLE:
Direct Current Generation in Carbon Nanotubes by Terahertz Field
AUTHORS:
Sulemana S. Abukari, Frederick Sam, Samuel Y. Mensah, Natalia G. Mensah, Rabiu Musah, Anthony Twum, Patrick M. Amoah, Alfred Owusu
KEYWORDS:
Carbon Nanotubes, Terahertz Fields, DC Voltage Generation, Negative Conductivity, Electron Scattering, Ballistic Transport
JOURNAL NAME:
World Journal of Condensed Matter Physics,
Vol.6 No.1,
February
29,
2016
ABSTRACT: We report on a theoretical investigation of a direct current generation in carbon nanotubes (CNTs) that are stimulated axially by terahertz (THz) field. We consider the kinetic approach based on the semiclassical Boltzmann’s transport equation with constant relaxation time approximation, together with the energy spectrum of an electron in the tight-binding approximation. Our results indicate that for strong THz-fields, there is simultaneous generation of DC current in the axial and circumferential directions of the CNTs, even at room temperature. We found that a THz-field can induce a negative conductivity in the CNTs that leads to the THz field induced DC current. For varying amplitude of the THz-field, the current density decreases rapidly and modulates around zero with interval of negative conductivity. The interval decreases with increasing the amplitude of the THz-field. We show that the THz-field can cause fast switching from a zero DC current to a finite DC current due to the quasi-ballistic transport, and that electron scattering is a necessary condition for switching.