Isotopically Enhanced Thermal Conductivity in Few-Layer Hexagonal Boron Nitride: Implications for Thermal Management

Elisha J M Mercado*, Chao Yuan, Yan Zhou, Jiahan Li, James H Edgar, Martin H H Kuball*

*Corresponding author for this work

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

Hexagonal boron nitride (h-BN) has been highlighted as a promising low-dimensional material for thermal management of next-generation devices. The theory predicts that the thermal conductivity of h-BN increases above the bulk value as the thickness is reduced, but previous reports on few-layer (5–11 layer) h-BN have shown the opposite trend. We investigated the effect of isotopic engineering on the thermal properties of 11-layer h-BN single-crystal flakes. The thermal conductivities of natural (22% 10B, 78% 11B) and monoisotopic (99% 10B) h-BN were determined by a modified optothermal Raman method in the range 300–400 K. At room temperature, values were as high as (630 + 90/–65) Wm–1K–1 for monoisotopic h-10BN and (405 + 87/–65) Wm–1K–1 for natural h-BN, corresponding to an isotopic enhancement of close to 60%. Both measured thermal conductivities either match or exceed previously reported values for bulk crystals, while the isotopic enhancement factor is approximately 35% higher for the isotopically enriched thin crystal compared to the equivalent bulk materials. The work presented here demonstrates isotopic engineering as a viable route to increased thermal conductivity in atomically thin h-BN, making it an outstanding platform material for thermal management in next-generation device applications.
Original languageEnglish
Number of pages9
JournalACS Applied Nano Materials
Early online date17 Nov 2020
DOIs
Publication statusE-pub ahead of print - 17 Nov 2020

Keywords

  • hexagonal boron nitride
  • isotope engineering
  • thermal conductivity
  • Raman
  • two-dimensional materials
  • interfacial thermal

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