Direct Current Generation in Carbon Nanotubes by Terahertz Field
Direct Current Generation in Carbon Nanotubes by Terahertz Field作者机构：Department of Physics Laser and Fibre Optics Centre University of Cape Coast Cape Coast Ghana Department of Mathematics University of Cape Coast Cape Coast Ghana Department of Applied Physics University for Development Studies Navorongo Ghana
出 版 物：《World Journal of Condensed Matter Physics》 (凝固态物理国际期刊（英文）)
年 卷 期：2016年第6卷第1期
页 面：56-62页
学科分类：08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学]
主 题：Carbon Nanotubes Terahertz Fields DC Voltage Generation Negative Conductivity Electron Scattering Ballistic Transport
摘 要：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.
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