Thermal conductivity reduction in silicon fishbone nanowires

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Physics

Background:

• Semiconductor nanowires are promising for thermoelectric devices due to inherently low thermal conductivity.
• Theoretical studies indicate that nanostructures like constrictions, pillars, or wings can further suppress thermal conductivity.

Purpose of the Study:

• To experimentally investigate heat conduction in silicon nanowires featuring periodic wings (fishbone nanowires).
• To determine the impact of wing geometry on the thermal conductivity of these nanostructures.

Main Methods:

• Fabrication and thermal conductivity measurement of silicon fishbone nanowires.
• Comparison with pristine nanowires and theoretical models.
• Phonon transport simulations and finite element modeling.

Main Results:

• Nanowire cross-section remains a key factor in thermal conductivity for fishbone structures.
• Periodic wings demonstrably reduce thermal conductivity compared to pristine nanowires.
• Wing depth has a more significant impact on reducing thermal conductivity than wing width, especially in narrower nanowires.

Conclusions:

• Fishbone silicon nanowires offer enhanced thermoelectric potential through reduced thermal conductivity.
• Optimizing wing depth is crucial for maximizing thermal conductivity reduction in these nanostructures.
• Experimental findings align with theoretical predictions and simulations, validating the design approach.