Tunable thermal conductivity of surface phonon polaritons in SiC thin film

Abstract

Abstract As an additional heat carrier besides phonons and electrons, the surface phonon polariton (SPhPs) possesses a large potential to increase the thermal conductivity. In this work, the influences of SPhP frequency, film thickness and film permittivity on the SPhP-contributed thermal conductivity of SiC thin films were probed. Results show that: there are two frequency zones which could lead to a much high thermal conductivity, i. e. the frequency which approaching zero and the frequency in singularity zone. The thermal conductivity decreases with the increase of the film thickness, following a power-function relationship, and a thin film with a thickness of 10-nm could have a thermal conductivity higher than 1 × 1 0 4 W·m−1·K−1. However, the experimental observation of this high thermal conductivity is still difficult because of the size effect of the film length. The thermal conductivity will increase with the decrease of the imaginary part of the film permittivity and/or increase of the real part of the film permittivity, and there is approximately a reciprocal dependence of thermal conductivity on the imaginary part of the film permittivity. The thermal conductivity could be tuned by several times with tailoring its permittivity through adding fillers in it or adding dopant in it. This work provides some potential methods to tune the SPhP thermal conductivity in SiC thin film, which could help its application in microscale heat dissipation.