The Impact of Topological States on the Thermoelectric Performance of p- and n-Type Sb2Te3/Bi2Se3-Multiwalled Carbon Nanotubes Heterostructured Networks

Abstract

The resistance and magnetoresistance of flexible thermoelectric p-type Sb2Te3-MWCNT, p-type Bi2Se3-MWCNT, and n-type Bi2Se3-MWCNT heterostructures were studied in the temperature range from 2 K to 300 K to reveal the conductance mechanisms governing the thermoelectric properties of these heterostructured networks. It was found that the conductance in heterostructured networks at different temperatures is governed by different processes and components of the networks. This effect was found to be related to the growth mechanisms of the Sb2Te3 and Bi2Se3 nanostructures on the MWCNT networks. At near-room temperatures, the Sb2Te3 and Bi2Se3 nanostructures were found to have the dominant contribution to the total conductance of the p-type Sb2Te3-MWCNT and n-type Bi2Se3-MWCNT networks. In turn, the conduction of p-type Bi2Se3-MWCNT heterostructured networks in a full temperature range and p-type Sb2Te3-MWCNT and n-type Bi2Se3-MWCNT heterostructured networks at temperatures below 30 K was governed by the MWCNTs; however, with the contribution from 2D topological states of Sb2Te3 and Bi2Se3 nanostructures, these were manifested by the weak antilocalization effect (WAL) cusps observed at temperatures below 5–10 K for all heterostructured networks considered in this work.