Enhanced Thermoelectric Performance of BST/WSe₂ Heterostructures Through Defect-Driven Microstructural Modifications.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Thermoelectric materials convert heat to electricity, crucial for waste heat recovery.
• Barium Strontium Titanate (BST) shows promise, but its thermoelectric efficiency needs improvement.
• Tungsten Diselenide (WSe2) is a 2D material with tunable electronic properties.

Purpose of the Study:

• To fabricate BST/WSe2 heterostructured films using dual-beam pulsed laser deposition.
• To investigate the impact of WSe2 incorporation on thermoelectric properties of BST.
• To optimize film deposition for superior thermoelectric performance.

Main Methods:

• Dual-beam pulsed laser deposition for BST/WSe2 heterostructure fabrication.
• Structural characterization to identify induced imperfections (e.g., dislocations, W atoms).
• Thermoelectric property measurements (Seebeck coefficient, electrical conductivity, thermal conductivity).

Main Results:

• Periodic WSe2 incorporation created structural imperfections, enhancing phonon scattering.
• WSe2's ambipolar nature allowed tuning of carrier concentration and energy filtering.
• Optimal deposition at 623 K yielded a power factor of ≈60.72 µW cm⁻² K⁻² at 447 K, surpassing previous reports.
• Moderate defect scattering at 623 K balanced mobility losses and thermal excitation.

Conclusions:

• Defect and interface engineering in BST/WSe2 heterostructures significantly enhances thermoelectric performance.
• The ambipolar semiconductor WSe2 is a key component for tuning thermoelectric properties.
• These findings pave the way for designing scalable, high-performance thermoelectric materials.