Energy transport across thin silicon-diamond films pair with minute vacuum gap at the interface

Energy transfer across the silicon-diamond thin films pairs is investigated due to temperature disturbance at the films edges. A minute vacuum gap satisfying the Casimir limit is considered at the interface films pair. The thermal boundary resistance across the film pair is formulated incorporating the cut-off mismatch model and the heat transfer due to thermal radiation is introduced across the vacuum gap because of temperature difference at the gap interface. The Boltzmann transport equation is used to account for the phonon intensity distribution in the films. The transient and frequency dependent solution of the Boltzmann equation is obtained numerically using the discrete ordinate method. A computer code developed is validated with the thermal conductivity data. It is found that the predictions of thermal conductivity agree well with the data presented in the previous study. The findings revealed that increasing gap size at the interface of the films pair increases interfacial temperature difference across the vacuum gap. Thermal radiation has less influence on the energy transport across the gap as compared to that takes place due to phonon jump across the gap interface.