Contactless near-field scanning thermoreflectance imaging

Area of Science:

• Materials Science
• Nanotechnology
• Physics

Background:

• Nanoscale thermal property determination is experimentally challenging.
• Existing methods often require physical contact, introducing thermal sinks and measurement artifacts.
• Conventional thermoreflectance is limited by diffraction at the nanoscale.

Purpose of the Study:

• To introduce a novel contactless scanning probe technique for nanoscale thermal imaging.
• To apply this technique to study the thermal conductivity of multilayer graphene thin films.
• To demonstrate the method's capability for high-resolution thermal property mapping.

Main Methods:

• Development and application of near-field scanning thermoreflectance imaging (NeSTRI).
• Utilizing an aperture-type near-field optical microscope for sub-wavelength resolution.
• Contactless thermoreflectance measurements on multilayer graphene on glass substrates.

Main Results:

• NeSTRI successfully determined the thermal conductivity of multilayer graphene platelets.
• Measured thermal conductivity values align with macroscopic predictions.
• Higher thermal conductivity was observed at specific crystallographic edges, demonstrating spatial resolution.

Conclusions:

• NeSTRI is a powerful new technique for contactless nanoscale thermal property imaging.
• The method is suitable for a wide range of nanostructured and nanoscale systems.
• NeSTRI provides insights into localized thermal transport phenomena.