Modelling heat conduction in polycrystalline hexagonal boron-nitride films

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Hexagonal boron-nitride (h-BN) is a promising material for thermal management applications due to its excellent intrinsic properties.
• Understanding heat transport in polycrystalline h-BN is crucial for optimizing its performance in various devices.
• Grain boundaries in polycrystalline materials often act as scattering sites, potentially reducing thermal conductivity.

Purpose of the Study:

• To investigate the thermal conductivity of polycrystalline hexagonal boron-nitride (h-BN) films using multiscale simulations.
• To determine the influence of grain size and grain configuration on heat conduction in h-BN films.
• To compare the thermal conductivity of polycrystalline h-BN with monocrystalline h-BN.

Main Methods:

• Extensive molecular dynamics (MD) simulations were performed on large atomistic models of polycrystalline h-BN.
• Equilibrium molecular dynamics (EMD) simulations were used to study the effect of average grain size on thermal conductivity at different temperatures.
• Finite element models (FEM) were constructed based on EMD results to analyze samples with larger grain sizes.

Main Results:

• The study explored the thermal conductivity of polycrystalline h-BN films with varying grain configurations (random and uniform).
• Thermal conductivity was found to be dependent on the average grain size and temperature.
• Multiscale simulations provided insights into heat conduction mechanisms across grain boundaries.

Conclusions:

• Polycrystalline h-BN films demonstrate high thermal conductivity, rivaling that of monocrystalline h-BN.
• Grain size plays a significant role in determining the overall thermal performance of h-BN films.
• The findings suggest that carefully engineered polycrystalline h-BN can be effectively utilized in applications requiring efficient heat dissipation.