Tunable power factor in fluorine-doped single-walled carbon nanotubes

Abstract

Herein, we present a tunable axial power factor (${\mathcal{P}}_{zz}$ ) in a nondegenerate fluorine-doped single-walled carbon nanotube (FSWCNT) using a tractable analytical approach. We derived the expressions for the electrical conductivity ($\sigma$ ), thermopower ($\alpha$ ), and power factor ($\mathcal{P}$ ) as a function of temperature. Additionally, we investigated the influence of doping concentration ($n_o$ ), constant electric field ($E_o$ ), and overlapping integrals (${\mathrm{\Delta }}_s$ and ${\mathrm{\Delta }}_z$ ) on their behavior. The intensity of the axial power factor (${\mathcal{P}}_{zz}$ ) and the operational temperature range can be tuned using the constant electric field, doping (carrier), and overlapping integrals, respectively. Applying the temperature field to the FSWCNT induces high-frequency carrier dynamics that critically depend on the magnitude of the temperature gradient. There exist two dynamic regimes that depend on the temperature gradient and carrier’s initial position. The carrier drifts through the FSWCNT and is allowed to perform drifting periodic orbits (in THz frequencies), resulting in the resonant enhancement of ${\mathcal{P}}_{zz}$ . Alternatively, inducing Bloch-like oscillations (in THz frequencies) cause ultra-high negative differential velocity without domain formation using an adequate temperature field. Moreover, we compare the ${\mathcal{P}}_{zz}$ of the FSWCNT to that of the superlattice (SL) (${\mathcal{P}}_{zz}^{SL}$ ), which shows that the ${\mathcal{P}}_{zz}$ of the FSWCNT is $8$ orders of magnitude greater than that of the SL. It is worth noting that the large ${\mathcal{P}}_{zz}$ obtained and the ability to tune the FSWCNT to operate at high temperatures make the FSWCNT a potential candidate for thermoelectric applications.