Effect of hot electrons on the electrical conductivity of carbon nanotubes under the influence of applied dc field

Abstract

The effect of hot electrons on the electrical conductivity of undoped single walled achiral carbon nanotubes (CNTs) under the influence of applied dc field along the tube axis is considered. We investigated semiclassically by solving the Boltzmann’s transport equation with and without the presence of the hot electrons source to derive the current densities. Plots of the normalized current density versus electric field strength of the CNTs in both scenarios reveal a negative differential conductivity (NDC). We observed that the intensity of the current density gradually decreases and shifts towards lower electric fields as the rate of hot electrons injection increases. Furthermore, with strong enough axial injection of the hot electrons, there is an upturn in the current density near 50 kV/cm and 75 kV/cm for a zigzag CNT and an armchair CNT, respectively. In this region of positive differential conductivity (PDC), the unwanted domain instability usually associated with NDC can be suppressed, suggesting a potential application in terahertz radiation at low and high (room) temperatures.