Right or Left moving ? Investigating Asymmetric Energy Dispersion Effects on Charge-Transfer between a Quantum Dot and Single-Walled Carbon Nanotube

Single-wall carbon nanotubes (SWCNT), two-dimensional hexagonal lattice of carbon atoms, possess unique mechanical, electrical, optical and thermal properties. SWCNT can be synthesized in diverse chiral indexes to determine certain attributes. This work theoretically investigates electron transport in different directions along SWCNT. The electron studied in this research transfers from the quantum dot that can possibly move to the right or left direction in SWCNT. Noticeably, the simulation in this work shows the asymmetric electron transport in that the probability to find the electron and the electron’s group velocity is different for each direction. Such a result can be traced theoretically by certain effects. That firstly is the curvature effect on SWCNT in which the hopping integral between π electrons from the flat graphene is altered, and another is curvature-inducing σ − π mixture. Due to these effects, the band structure of SWCNT is asymmetric in certain chiral indexes leading to the asymmetric electron transport. Our results exhibit that the zigzag chiral indexes is the only type making electron transport symmetry that is different to the result from the other chiral index types which are the armchair and chiral. This work also illustrates the characteristic of the electron wave function propagating from the initial point to the tip of the tube over time, and the current density of the probability in specific times. Additionally, our research simulates the result from the dipole interaction between the electron in QD and the tube that impacts the lifetime of the electron being in QD. The simulation portrays that the more dipole interaction encourages the electron transfer to the tube, thereby shortening the lifetime. We as well suggest the reversed electron transfer from the tube to QD that the time duration of such transfer is much less than the opposite transfer owing to the different orbital of the electron’s states. The exploration in this work can be applied to carbon nanotube products, such as solar cells, artificial antennas, quantum computers and other coming technologies, for various advantages.