Tuning Interfacial Phonon Transport in GaN/WSSe van der Waals Heterostructure toward High-Efficiency Thermoelectric...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Gallium Nitride (GaN) exhibits limited thermoelectric performance due to high thermal conductivity and low electrical conductance.
• This inefficiency hinders its application in power generation from thermal gradients.

Purpose of the Study:

• To propose and investigate the GaN/WSSe van der Waals (vdW) heterostructure as a means to enhance thermoelectric performance.
• To explore the structural, electronic, and thermal transport properties of the GaN/WSSe vdW heterostructure.

Main Methods:

• Density Functional Theory (DFT) was employed to analyze structural stability, electronic band alignment, and energetic properties.
• The nonequilibrium Green's function (NEGF) formalism within the Landauer-Büttiker framework was used to study thermoelectric transport.
• Phonon scattering and electronic transport channels were investigated to understand their impact on performance.

Main Results:

• The Se-4 and S-3 stacking models of GaN/WSSe demonstrated high adhesion energies and a type-II staggered band alignment, facilitating charge carrier separation.
• The heterostructure exhibited suppressed electron scattering and enhanced phonon scattering, leading to improved electrical conductance and reduced thermal conductivity.
• High thermoelectric figure of merit (ZT) values of 3.99 and 4.23 were achieved at elevated temperatures.

Conclusions:

• The GaN/WSSe vdW heterostructure effectively overcomes the intrinsic limitations of GaN for thermoelectric applications.
• This engineered heterostructure shows significant promise for efficient thermoelectric power generation.