The atomic-mass convergence mechanism in interfacial thermal transport of metal-semiconductor heterojunctions

ZY Wang and DH Li and JY Wang and LQ Chen and J Zhu and DW Tang, SURFACES AND INTERFACES, 72, 107085 (2025).

DOI: 10.1016/j.surfin.2025.107085

Understanding interfacial thermal transport in metal-semiconductor systems is essential for advancing thermal management in nanoscale electronic devices. While vibrational coupling is traditionally viewed as the main factor determining thermal boundary conductance, atomic mass differences can also significantly influence interfacial heat transfer. In this study, we investigate the atomic-mass effect by constructing a series of metal--semiconductor heterojunctions with controlled mass distributions. Time-domain thermoreflectance measurements on Al/Si, Al/Ge, Mo/Si, and Mo/Ge structures show that, within the same metal system, smaller single-atom mass differences yield higher TBC. However, this trend does not extend across different metals, which has been confirmed by our Molecular dynamics simulations as well. Phonon transmission analysis reveals that in systems with different atomic masses, TBC is influenced by phonons in different frequency ranges. Phonon participation ratio calculations further reveal that the beneficial effects of mass convergence surpass the adverse effects of phonon localization, resulting in an overall increase in TBC. We further examine several mass-related parameters and find that only the average mass difference at the interface shows a consistent monotonic relationship with TBC, regardless of material type. These findings offer new insights into nanoscale heat transport and highlight the utility of average atomic mass difference as a reliable descriptor for predicting interfacial thermal transport in metal-semiconductor heterojunctions.

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