Tuning interfacial thermal conductance by combining single vacancy and atomic mass variation in crystalline and...

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Interfacial thermal resistance hinders heat dissipation in nanoscale semiconductor devices.
• Varying atomic mass and introducing vacancy defects are known methods to enhance interfacial thermal conductance (ITC).
• The combined effect of atomic mass variation and vacancy defects on ITC is not well understood.

Purpose of the Study:

• To investigate the influence of single vacancies on ITC in crystalline and amorphous interfaces with varied atomic masses (Si-Ge).
• To understand the role of vacancy location and atomic mass on phonon transmission and ITC.
• To provide insights for engineering high-ITC interfaces in semiconductor heterostructures.

Main Methods:

• Utilized the mode-resolved atomistic Green's function method.
• Analyzed the impact of single vacancy defects on ITC for both crystalline and amorphous interfaces.
• Performed spectral and modal analyses of phonon transmission.

Main Results:

• For amorphous interfaces, ITC peaks at a specific atomic mass, and vacancies consistently reduce ITC by suppressing phonon transmission.
• For crystalline interfaces, vacancies can further enhance ITC beyond atomic mass variation alone.
• Vacancy-induced enhancement in crystalline interfaces depends on location and atomic mass, optimizing phonon transmission in medium and high frequencies.

Conclusions:

• Single vacancies have contrasting effects on ITC in amorphous versus crystalline interfaces.
• Vacancy engineering in crystalline interfaces offers a pathway to enhance thermal transport, especially at unfavorable atomic mass compositions.
• The findings provide crucial guidance for designing advanced semiconductor heterostructures with improved thermal management.