A Modified Theoretical Model to Accurately Account for Interfacial Roughness in Predicting the Interfacial Thermal Conductance

Yingying Zhang,Yi Zang,Nuo Yang,Xiaojia Wang,Dengke Ma

doi:10.3389/fenrg.2018.00048

Yingying Zhang, Yi Zang + Show 3 more

Open Access

https://doi.org/10.3389/fenrg.2018.00048

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Abstract

The acoustic mismatch model and the diffuse mismatch model have been widely used to predict the thermal interface conductance. However, the acoustic mismatch model (diffuse mismatch model) is based on the hypothesis of a perfectly smooth (completely disordered) interface. Here, we present a new modified model, named as the mixed mismatch model, which considers the roughness/bonding at the interface. By taking partially specular and partially diffuse transmissions into account, the mixed mismatch model can predict the thermal interface conductance with arbitrary roughness. The proportions of specular and diffuse transmission are determined by the interface roughness which is described by the interfacial density of states. It shows that the predicted results of the mixed mismatch model match well with the values of molecular dynamics simulation and experimental data.

Highlights

Thermal transport across interface is an important issue for microelectronics, photonics, and thermoelectric devices, and has been studied both experimentally and theoretically recently. [1,2] Generally, the thermal interface conductance (TIC) is used to evaluate the physical properties of thermal transport in devices and materials[3], such as composites[4], superlattices[5], thin-film multilayers[6], nanoscale devices[7], and nanocrystalline materials[8]
These two models have advanced the understanding of thermal transport across interface, both the acoustic mismatch model (AMM) and diffuse mismatch model (DMM) purely consider the bulk properties, and ignore the interfacial roughness, phonon states[10] and inelastic scattering, which leads to the inaccuracy of the two models.[1,11]
Some works have improved the accuracy of the AMM and DMM, and sophisticated modifications to the original models that account for the inelastic scattering have been proposed

Summary

Introduction

Thermal transport across interface is an important issue for microelectronics, photonics, and thermoelectric devices, and has been studied both experimentally and theoretically recently. [1,2] Generally, the thermal interface conductance (TIC) is used to evaluate the physical properties of thermal transport in devices and materials[3], such as composites[4], superlattices[5], thin-film multilayers[6], nanoscale devices[7], and nanocrystalline materials[8]. Chen proposed the partially diffuse and partially specular interface scattering model to predict the thermal conductivity of superlattice structures[18]. Based on partially specular and partially diffuse transmissions, by taking interface states into account, the MMM can predict the TIC with arbitrary roughness and overcomes the shortage of AMM and DMM.

Results

Conclusion