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Ultrahigh thermal conductivity in isotope-enriched cubic boron nitride
Ke Chen1, Bai Song2, Navaneetha K Ravichandran3
1Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Science (New York, N.Y.)
|January 11, 2020
Summary
Cubic boron nitride (cBN) crystals with enriched boron isotopes exhibit ultrahigh thermal conductivity (κ) exceeding 1600 W/m·K. This discovery highlights cBN
Area of Science:
- Materials Science
- Solid State Physics
- Crystal Growth
Background:
- High thermal conductivity (κ) materials are crucial for technological advancements and fundamental scientific understanding.
- Isotopic composition significantly influences material properties, including thermal transport.
Purpose of the Study:
- To investigate the impact of boron isotope enrichment on the thermal conductivity of cubic boron nitride (cBN).
- To compare the isotopic enhancement of κ in cBN with other boron-based compounds like boron phosphide and boron arsenide.
- To evaluate the potential of cBN for advanced electronic and optoelectronic applications.
Main Methods:
- Growth of cubic boron nitride (cBN) crystals with controlled abundance of boron isotopes (10B and 11B).
- Measurement of thermal conductivity (κ) at room temperature for isotopically enriched cBN samples.
- Comparative analysis of isotopic effects on κ in cBN, boron phosphide, and boron arsenide.
Main Results:
- Achieved ultrahigh thermal conductivity (κ) greater than 1600 watts per meter-kelvin in isotopically enriched cBN at room temperature.
- Observed significantly lower isotopic enhancement of κ in boron phosphide and boron arsenide compared to cBN.
- Demonstrated that isotopic mass disorder has a reduced effect on phonons in boron phosphide and boron arsenide.
Conclusions:
- Isotopically engineered cBN exhibits exceptional thermal conductivity, surpassing that of many established materials.
- The wide bandgap (6.2 eV) of cBN, combined with its ultrahigh κ, positions it as a leading candidate for thermal management in microelectronics.
- cBN holds significant promise for high-power electronics and optoelectronics applications requiring superior thermal performance.
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