Origins of Minimized Lattice Thermal Conductivity and Enhanced Thermoelectric Performance in WS2/WSe2 Lateral Superlattice | JoVE Visualize

Origins of Minimized Lattice Thermal Conductivity and Enhanced Thermoelectric Performance in WS₂/WSe₂ Lateral Superlattice

Yonglan Hu¹, Tie Yang², Dengfeng Li¹

¹School of Science, Chongqing University of Posts and Telecommunications, Chongqing 400065, China.

ACS Omega|March 29, 2021

View abstract on PubMed

Summary

This study enhances thermoelectric (TE) performance in WS2/WSe2 lateral superlattices by reducing thermal conductivity. The novel structure shows potential for efficient TE materials with a figure of merit (zT) exceeding 1.

Area of Science:

Materials Science
Condensed Matter Physics
Nanotechnology

Background:

Two-dimensional transition metal dichalcogenides like WS2 are promising for thermoelectric (TE) applications.
Improving the TE figure of merit (zT) is crucial for efficient energy conversion.
Lateral superlattices (LS) offer a pathway to tune material properties.

Purpose of the Study:

To investigate the TE performance enhancement of WS2-based materials.
To explore the potential of WS2/WSe2 lateral superlattices for improved TE applications.
To understand the underlying mechanisms responsible for TE property modifications.

Main Methods:

Experimental preparation of WS2/WSe2 lateral superlattice crystals.
First-principles calculations based on density functional theory (DFT).
Boltzmann transport equation for simulating electronic and thermal transport properties.

Main Results:

Remarkable enhancement of the TE figure of merit (zT) in WS2/WSe2 LS compared to monolayer WS2.
Significant reduction in lattice thermal conductivity due to enhanced anharmonic phonon scattering.
High electronic transport symmetry and potential for high Seebeck coefficients (S) due to unique band structures and stair-like density of states (DOS).
Achieved optimal zT exceeding 1 at 400 K for p-type doping, driven by high hole mobility.

Conclusions:

The WS2/WSe2 lateral superlattice is an effective strategy for boosting TE performance.
Reduced thermal conductivity and favorable electronic band structure contribute to high zT.
These findings highlight the potential of WS2/WSe2 LS as efficient p-type thermoelectric materials.