Giant reduction of thermal conductivity in twinning superlattice InAsSb nanowires

TL;DR

This study demonstrates that intentionally introduced twin planes in InAsSb nanowires drastically reduce thermal conductivity by an order of magnitude, significantly enhancing thermoelectric efficiency without harming electrical properties.

Contribution

First experimental measurement of electrical and thermal transport in twinning superlattice nanowires, revealing a new approach to improve thermoelectric performance.

Findings

Thermal conductivity decreased by an order of magnitude.

Electrical transport properties remained unaltered.

Thermoelectric figure of merit (ZT) increased tenfold.

Abstract

Semiconductor nanostructures hold great promise for high-efficiency waste heat recovery exploiting thermoelectric energy conversion, a technological breakthrough that could significantly contribute to providing environmentally friendly energy sources as well as in enabling the realization of self-powered biomedical and wearable devices. A crucial requirement in this field is the reduction of the thermal conductivity of the thermoelectric material without detrimentally affecting its electrical transport properties. In this work we demonstrate a drastic reduction of thermal conductivity in III-V semiconductor nanowires due to the presence of intentionally realized periodic crystal lattice twin planes. The electrical and thermal transport of these nanostructures, known as twinning superlattice nanowires, have been probed and compared with their twin-free counterparts, showing a one order of magnitude decrease of thermal conductivity while maintaining unaltered electrical transport properties, thus yielding a factor ten enhancement of the thermoelectric figure of merit, ZT. Our study reports for the first time the experimental measurement of electrical and thermal properties in twinning superlattice nanowires, which emerge as a novel class of nanomaterials for high efficiency thermoelectric energy harvesting.