Phonon transfer in silicon-diamond films: Influence of thermal boundary resistance on acoustic phonon intensities

Abstract

Thermal energy transfer across two-dimensional silicon and diamond thin films are considered and the influence of the thermal boundary resistance, due to mismatching of properties, on the acoustic phonon transport characteristics is studied. The transient form of the Boltzmann equation with frequency dependency of phonons is incorporated simulating the phonon transport. Thermal boundary resistance is considered incorporating mismatches of interface conditions of films, namely cut-off and diffusive models. The ratios of longitudinal and transverse acoustic phonon wave intensities because mismatch models (cut-off and diffusive mismatches) are predicted for temperature oscillating boundary condition at the silicon edge. It is found that the ratio of the longitudinal acoustic phonon intensities ratio because of mismatch models (cut-off over diffusive) does not behave exactly the oscillation of temperature at the edge of the silicon film due to scattering of phonons in the films. The same arguments are applicable for the ratio of transverse acoustic phonon intensities because of the interfacial mismatch models (cut-off over diffusive). The consideration of the phonon frequencies cut-off results in the ballistic phonon transfer in between films, which lowers the interfacial thermal resistance.