Nanosecond transient thermoreflectance method for characterizing anisotropic thermal conductivity

Area of Science:

• Materials Science
• Thermal Physics
• Nanotechnology

Background:

• Characterizing anisotropic thermal properties is crucial for advanced materials.
• Transient thermoreflectance (TTR) is a powerful technique for thermal property measurement.
• Distinguishing between in-plane and out-of-plane thermal conductivity can be challenging.

Purpose of the Study:

• To present a novel method for characterizing anisotropic thermal properties using nanosecond TTR.
• To develop an analytical heat transfer model for the TTR signal.
• To enable simultaneous determination of out-of-plane and in-plane thermal conductivities.

Main Methods:

• Derivation of an analytical heat transfer model for TTR signals.
• Exploiting the distinct time-scale sensitivity of the TTR signal to in-plane and out-of-plane heat conduction.
• Applying the method to materials like molybdenum disulfide, hexagonal boron nitride, and pyrolytic graphite.

Main Results:

• The TTR signal's sensitivity to both out-of-plane and in-plane heat conduction was demonstrated.
• A method for simultaneously determining anisotropic thermal conductivities was established.
• Validation of the method through experimental assessment on selected materials.

Conclusions:

• The presented nanosecond TTR method offers a reliable approach for characterizing anisotropic thermal properties.
• This technique facilitates the simultaneous measurement of in-plane and out-of-plane thermal conductivities.
• The findings are applicable to various layered and anisotropic materials.