Near-field radiative heat transfer between parallel structures in the deep subwavelength regime

Area of Science:

• Nanoscale heat transfer
• Solid-state physics
• Thermal engineering

Background:

• Near-field thermal radiation exhibits unique characteristics at deep subwavelength separations and large thermal gradients.
• Potential applications include thermal transport control and efficient energy generation.
• Experimental realization has been hindered by challenges in maintaining nanoscale gaps and large temperature gradients while suppressing conduction.

Purpose of the Study:

• To experimentally demonstrate near-field radiative heat transfer between parallel silicon carbide (SiC) nanobeams in the deep subwavelength regime.
• To overcome the experimental limitations of maintaining stable nanometer-scale separations under large thermal gradients.

Main Methods:

• Utilized high-precision micro-electromechanical systems (MEMS) to control the separation between SiC nanobeams.
• Employed high tensile stress in nanobeams to enhance mechanical stability and prevent thermal buckling.
• Maintained large thermal gradients across the nanobeam structures.

Main Results:

• Achieved an enhancement of radiative heat transfer nearly two orders of magnitude greater than the far-field limit at a 42 nm separation.
• Successfully maintained a temperature gradient of 260 K between surfaces separated by approximately 100 nm.
• Demonstrated stable nanoscale separation under significant thermal gradients.

Conclusions:

• The study successfully demonstrates controlled near-field radiative heat transfer in the deep subwavelength regime.
• The developed method enables stable nanoscale gap control under large thermal gradients, paving the way for advanced thermal management and energy harvesting technologies.