High thermal conductivity of high-quality monolayer boron nitride and its thermal expansion

Qiran Cai, Declan Scullion, Wei Gan, Aleksey Falin, Shunying Zhang, Kenji Watanabe, Takashi Taniguchi, Ying Chen, Elton J. G. Santos, Lu Hua Li

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)
149 Downloads (Pure)

Abstract

Heat management becomes more and more critical, especially in miniaturized modern devices, so the exploration of highly thermally conductive materials with electrical insulation and favorable mechanical properties is of great importance. Here, we report that high-quality monolayer boron nitride (BN) has a thermal conductivity (\k{appa}) of 751 W/mK at room temperature. Though smaller than that of graphene, this value is larger than that of cubic boron nitride (cBN) and only second to those of diamond and lately discovered cubic boron arsenide (BAs). Monolayer BN has the second largest \k{appa} per unit weight among all semiconductors and insulators, just behind diamond, if density is considered. The \k{appa} of atomically thin BN decreases with increased thickness. Our large-scale molecular dynamic simulations using Green-Kubo formalism accurately reproduce this trend, and the density functional theory (DFT) calculations reveal the main scattering mechanism. The thermal expansion coefficients (TECs) of monolayer to trilayer BN at 300-400 K are also experimentally measured, and the results are comparable to atomistic ab initio DFT calculations in a wider range of temperatures. Thanks to its wide bandgap, high thermal conductivity, outstanding strength, good flexibility, and excellent thermal and chemical stability, atomically thin BN is a strong candidate for heat dissipation applications, especially in the next generation of flexible electronic devices.
Original languageEnglish
Article numbereaav0129
Number of pages8
JournalScience Advances
Volume5
Issue number6
DOIs
Publication statusPublished - 07 Jun 2019

Keywords

  • Condensed Matter - Materials Science

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