Diameter dependence of thermoelectric power of semiconducting carbon nanotubes
Journal
Physical Review B - Condensed Matter and Materials Physics
Journal Volume
92
Journal Issue
16
Start Page
165426
ISSN
1550235X
10980121
Date Issued
2015
Author(s)
Abstract
We calculate the thermoelectric power (or thermopower) of many semiconducting single wall carbon nanotubes (s-SWNTs) within a diameter range 0.5-1.5nm by using the Boltzmann transport formalism combined with an extended tight-binding model. We find that the thermopower of s-SWNTs increases as the tube diameter decreases. For some s-SWNTs with diameters less than 0.6nm, the thermopower can reach a value larger than 2000μV/K at room temperature, which is about 6 to 10 times larger than that found in commonly used thermoelectric materials. The large thermopower values may be attributed to the one dimensionality of the nanotubes and to the presence of large band gaps of the small-diameter s-SWNTs. We derive an analytical formula to reproduce the numerical calculation of the thermopower and we find that the thermopower of a given s-SWNT is directly related with its band gap. The formula also explains the shape of the thermopower as a function of tube diameter, which looks similar to the shape of the so-called Kataura plot of the band gap dependence on tube diameter.
Publisher
American Physical Society revtex@aps.org
Type
journal article