Lateral transition metal dichalcogenide heterostructures for high efficiency thermoelectric devices

TL;DR

This study demonstrates that lateral heterostructures of transition-metal dichalcogenides significantly enhance thermoelectric efficiency, with some configurations achieving five times higher ZT than pristine monolayers, opening new avenues for 2D thermoelectric devices.

Contribution

The paper introduces a multiscale quantum transport framework to evaluate thermoelectric performance of lateral TMDC heterostructures, revealing band alignment as a key factor in efficiency enhancement.

Findings

n-type WS2 with WSe2 inclusions has ZT five times higher than pristine WS2

p-type MoSe2 with WSe2 inclusions doubles the ZT of pristine MoSe2

Peak power factors surpass previous reports for gapped 2D monolayers at room temperature

Abstract

Increasing demands for renewable sources of energy has been a major driving force for developing efficient thermoelectric materials. Two-dimensional (2D) transition-metal dichalcogenides (TMDC) have emerged as promising candidates for thermoelectric applications due to their large effective mass and low thermal conductivity. In this article, we study the thermoelectric performance of lateral TMDC heterostructures within a multiscale quantum transport framework. Both $n$-type and $p$-type lateral heterostructures are considered for all possible combinations of semiconducting TMDCs: MoS$_2$, MoSe$_2$, WS$_2$, and WSe$_2$. The band alignment between these materials is found to play a crucial in enhancing the thermoelectric figure-of-merit ($ZT$) and power factor far beyond those of pristine TMDCs. In particular, we show that the room-temperature $ZT$ value of $n$-type WS$_2$ with WSe$_2$ triangular inclusions, is five times larger than the pristine WS$_2$ monolayer. $p$-type MoSe$_2$ with WSe$_2$ inclusions is also shown to have a room-temperature $ZT$ value about two times larger than the pristine MoSe$_2$ monolayer. The peak power factor values calculated here, are the highest reported amongst gapped 2D monolayers at room temperature. Hence, 2D lateral TMDC heterostructures open new avenues to develop ultra-efficient, planar thermoelectric devices.