Thermal transport across grain boundaries in polycrystalline silicene: a multiscale modeling

TL;DR

This study investigates how grain boundaries and strain influence thermal transport in polycrystalline silicene using multiscale modeling, revealing tunable thermal properties relevant for material design.

Contribution

It provides the first detailed multiscale analysis of thermal transport across grain boundaries in silicene, including effects of strain and grain size.

Findings

Kapitza conductance at room temperature is approximately 2.56*10^9 W/m2K.

Interfacial thermal resistance is unaffected by temperature but can be controlled by strain.

Thermal conductivity can be modulated by up to an order of magnitude through grain size tuning.

Abstract

During the fabrication process of large scale silicene through common chemical vapor deposition (CVD) technique, polycrystalline films are quite likely to be produced, and the existence of Kapitza thermal resistance along grain boundaries could result in substantial changes of their thermal properties. In the present study, the thermal transport along polycrystalline silicene was evaluated by performing a multiscale method. Non-equilibrium molecular dynamics simulations (NEMD) was carried out to assess the interfacial thermal resistance of various constructed grain boundaries in silicene as well as to examine the effects of tensile strain and the mean temperature on the interfacial thermal resistance. In the following stage, the effective thermal conductivity of polycrystalline silicene was investigated considering the effects of grain size and tensile strain. Our results indicate that the average values of Kapitza conductance at grain boundaries at room temperature were estimated nearly 2.56*10^9 W/m2K and 2.46*10^9 W/m2K through utilizing Tersoff and Stillinger-Weber interatomic potentials, respectively. Also, in spite of the mean temperature whose increment does not change Kapitza resistance, the interfacial thermal resistance can be controlled by applying strain. Furthermore, it was found that, by tuning the grain size of polycrystalline silicene, its thermal conductivity can be modulated up to one order of magnitude.