Boron and Nitrogen Isotope Effects on Hexagonal Boron Nitride Properties

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Hexagonal boron nitride (hBN) is a 2D material with unique properties suitable for advanced electronic, optoelectronic, and quantum devices.
• Previous isotopic purification of hBN focused on boron isotopes, while nitrogen remained naturally abundant (primarily ¹⁴N).

Purpose of the Study:

• To extend isotopic purification of hBN to include nitrogen isotopes, specifically ¹⁵N.
• To investigate the impact of single-isotope enrichment of both boron and nitrogen on hBN properties.

Main Methods:

• Growth of four hBN crystal configurations (h¹⁰B¹⁴N, h¹¹B¹⁴N, h¹⁰B¹⁵N, h¹¹B¹⁵N) using the metal flux method.
• Utilized single-isotope enriched boron and nitrogen sources (>99% purity).
• Employed nickel and chromium as the solvent for crystal growth.
• Characterization through in-depth Raman and photoluminescence spectroscopies.

Main Results:

• Successful growth of high-quality monoisotopic hBN crystals in all four configurations.
• Demonstrated that ¹⁵N-purified hBN exhibits vibrational and optical properties comparable to state-of-the-art ¹⁴N-purified hBN.

Conclusions:

• The synthesis of high-quality h¹⁰B¹⁴N, h¹¹B¹⁴N, h¹⁰B¹⁵N, and h¹¹B¹⁵N opens new avenues for controlling thermal conductivity in heat management applications.
• These isotopically pure hBN materials offer advanced functionalities for next-generation quantum technologies.