Tuning thermal conductance across sintered silicon interface by local nanostructures

• The first measurement of thermal boundary conductance across sintered interfaces.
• Large controllability of Si–Si thermal conductance by local oxide nanostructures.
• New route to reduce thermal conductivity of Si nanocomposite thermoelectrics.
• Potential to make the thermal conductivity approach the amorphous limit.

A large reduction of heat conduction through silicon–silicon sintered interface by local oxide nanostructures is quantitatively demonstrated by a newly developed method to directly measure thermal boundary conductance across bonded interfaces. Together with the theoretical analysis that relates the thermal boundary conductance to thermal conductivity of densely-packed bulk nanocrystalline silicon, we identify a route to significantly reduce the thermal conductivity from the state-of-art value, even to approach the amorphous silicon value. The finding is useful for designing nanostructured bulk silicon thermoelectrics.

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