Thermal diffusivity microscope: Zooming in on anisotropic heat transport

Area of Science:

• Materials Science
• Condensed Matter Physics
• Thermal Engineering

Background:

• Anisotropic heat-conducting materials are vital for electronic, optoelectronic, and thermoelectric devices.
• Accurate measurement of anisotropic thermal diffusivity is challenging in polycrystalline systems.

Purpose of the Study:

• To develop a novel, high-resolution, local measurement technique for anisotropic thermal diffusivity.
• To overcome limitations of existing methods for characterizing thermal transport in anisotropic materials.

Main Methods:

• Demonstration of a unique thermal diffusivity microscope.
• Utilizing a micro four-point probe for fast, nondestructive scanning.
• Measuring anisotropic thermal diffusivity via thermal delay from a single heater.

Main Results:

• The microscope enables high-resolution local measurements of anisotropic thermal diffusivity.
• Anisotropy measurements correlate strongly with crystallographic orientation in Bismuth Telluride (Bi2Te3).
• Lattice contribution is dominant in both in-plane and out-of-plane heat transport.

Conclusions:

• The developed thermal diffusivity microscope is a robust, direct, and nondestructive technique.
• This method facilitates accurate characterization of anisotropic thermal transport in materials.
• Findings are crucial for optimizing thermal management in advanced devices.