Interface-Engineered Bi_0.5Sb_1.5Te₃/WSe₂ Heterostructures for Enhanced Thermoelectric Performance

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Thermoelectric materials convert heat to electricity.
• Optimizing heterostructures is key to improving thermoelectric efficiency.
• Understanding interfacial effects in layered materials is crucial.

Purpose of the Study:

• To investigate the impact of interfacial structure and composition on the thermoelectric properties of BST/WSe2 heterostructures.
• To correlate structural characteristics with thermoelectric performance metrics.
• To explore mechanisms enhancing the Seebeck coefficient and power factor.

Main Methods:

• Pulsed laser deposition for BST/WSe2 heterostructure fabrication.
• X-ray diffraction and Cs-STEM for structural and compositional analysis.
• Temperature-dependent electrical transport measurements.

Main Results:

• High crystallinity and lattice compression observed in BST/WSe2 heterostructures.
• Interfacial strain and moiré patterns influence band structure, leading to band flattening.
• Enhanced electrical conductivity and high Seebeck coefficients (>430 µV K-1) due to thermally activated carriers and interfacial energy filtering.
• Formation of internal p-n junction-like regions within WSe2 domains tunes carrier concentration.
• Thermally stable power factor exceeding 50 µW cm-1 K-2 achieved.

Conclusions:

• Interfacial engineering in BST/WSe2 heterostructures is a viable strategy for high-performance thermoelectrics.
• Lattice strain and moiré reconstruction play a significant role in enhancing thermoelectric properties.
• The observed phenomena pave the way for designing advanced thermoelectric materials.