Thermal characteristics and phonon transport in diamond and silicon thin films

The effect of temperature oscillation at the film edge on the phonon transport is examined in two-dimensional silicon and diamond films.Anumerical solution of transient frequency-dependent Boltzmann equation is presented to account for the phonon transport in the thin films. Three different frequencies of temperature oscillation are incorporated in the analysis to demonstrate the thermal response of thin films to temperature oscillation. It is found that equivalent equilibrium temperature demonstrates diffusive behavior in the close region of the film edge as similar to those observed for the diffusive limit. This behavior is associated with the ineffective contribution of the in-phase phonons to the phonon scattering in the film. As the distance increases along the film width, the influence of temperature oscillation on the equivalent equilibrium temperature becomes negligibly small.