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Thickness-Dependent Cross-Plane Thermal Conductivity Measurements of Exfoliated Hexagonal Boron Nitride.
| Content Provider | Europe PMC |
|---|---|
| Author | Jaffe, Gabriel R. Smith, Keenan J. Watanabe, Kenji Taniguchi, Takashi Lagally, Max G. Eriksson, Mark A. Brar, Victor W. |
| Copyright Year | 2023 |
| Abstract | Submicrometer-thicklayers of hexagonal boron nitride (hBN) exhibithigh in-plane thermal conductivity and useful optical properties,and serve as dielectric encapsulation layers with low electrostaticinhomogeneity for graphene devices. Despite the promising applicationsof hBN as a heat spreader, the thickness dependence of its cross-planethermal conductivity is not known, and the cross-plane phonon meanfree paths (MFPs) have not been measured. We measure the cross-planethermal conductivity of hBN flakes exfoliated from bulk crystals.We find that submicrometer thick flakes exhibit thermal conductivitiesup to 8.1 ± 0.5 W m–1 K–1 at 295 K, which exceeds previously reported bulk values by morethan 60%. Surprisingly, the average phonon mean free path is foundto be several hundred nanometers at room temperature, a factor of5 larger than previous predictions. When planar twist interfaces areintroduced into the crystal by mechanically stacking multiple thinflakes, the cross-plane thermal conductivity of the stack is foundto be a factor of 7 below that of individual flakes with similar totalthickness, thus providing strong evidence that phonon scattering attwist boundaries limits the maximum phonon MFPs. These results haveimportant implications for hBN integration in nanoelectronics andimprove our understanding of thermal transport in two-dimensionalmaterials. |
| ISSN | 19448244 |
| Journal | ACS Applied Materials & Interfaces |
| Volume Number | 15 |
| PubMed Central reference number | PMC9999343 |
| Issue Number | 9 |
| PubMed reference number | 36848224 |
| e-ISSN | 19448252 |
| DOI | 10.1021/acsami.2c21306 |
| Language | English |
| Publisher | American Chemical Society |
| Publisher Date | 2023-02-27 |
| Access Restriction | Open |
| Rights License | Permits non-commercial access and re-use, provided that author attribution and integrity are maintained; but does not permit creation of adaptations or other derivative works (https://creativecommons.org/licenses/by-nc-nd/4.0/). © 2023 The Authors. Published by American Chemical Society |
| Subject Keyword | phonon meanfree path hBN cross-plane thermal conductivity twist interface |
| Content Type | Text |
| Resource Type | Article |
| Subject | Nanoscience and Nanotechnology Medicine Materials Science |
