International Journal of Physics | Vol. 16, No. 1, January 2025 | pp. 1–8
DOI: 10.46882/2025/IJP/000177
Research Article
Title: Thermal Dispersion Parameters and Phonon Scattering Dynamics across Silicon-Gallium Nitride Heterojunctions
Names of Authors: D. W. Meyer¹, H. L. Mueller²
Authors’ Affiliations:
¹ Institute of Physics, Karlsruher Institut für Technologie, Karlsruhe, Germany
² Institut für Kernphysik, Karlsruher Institut für Technologie, Karlsruhe, Germany
Abstract: Effectively dissipating high thermal fluxes across heavily mismatched semiconductor boundary layers is a vital milestone for developing next-generation wide-bandgap radio-frequency electronics and compact power conversion switches. This paper utilizes molecular dynamics simulations to quantify thermal dispersion parameters and track acoustic phonon wavepacket scattering at mismatched silicon-gallium nitride (Si-GaN) heterojunctions. We constructed atomistic models using the optimized Tersoff empirical potentials, incorporating varying concentrations of interfacial dislocation networks and localized point vacancy defects. Longitudinal and transverse acoustic phonon wavepackets were generated with narrow frequency spreads centered between 3.0 THz and 12.0 THz. The computational data demonstrate that high-frequency acoustic phonons (f greater than 6.5 THz) undergo strong diffuse scattering at the rough interface, dropping the calculated transmission coefficient from 0.74 down to 0.15. This transport degradation is driven by severe acoustic impedance mismatch and localized interface vibrational modes. The overall interfacial thermal conductance was calculated to decrease by 48.0% when the interface defect density scaled from 1.0% to 5.0% at 300.0 K. These molecular dynamics calculations clarify the atomic-scale paths limiting heat carrier propagation, helping engineers design targeted thermal management interfaces for high-power electronics.
Keywords: Thermal conductance; phonon wavepacket; molecular dynamics; interface defects; silicon-gallium nitride; electronics cooling
Manuscript Timeline: Received: October 12, 2024; Revised: November 22, 2024; Accepted: December 10, 2024; Published: January 15, 2025
Citation: Meyer, D. W., & Mueller, H. L. (2025). Thermal Dispersion Parameters and Phonon Scattering Dynamics across Silicon-Gallium Nitride Heterojunctions. International Journal of Physics, 16(1), 1–8.
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