Ballistic vs. diffusive heat transfer across nanoscopic films of layered crystals
- Department of Materials Science and Engineering, and Rensselaer Nanotechnology Center, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)
We use non-equilibrium molecular dynamics to study the heat transfer mechanism across sandwich interfacial structures of Si/n-atomic-layers/Si, with 1 ≤ n ≤ 20 and atomic layers composed of WSe{sub 2} and/or graphene. In the case of WSe{sub 2} sheets, we observe that the thermal resistance of the sandwich structure is increasing almost linearly with the number of WSe{sub 2} sheets, n, indicating a diffusive phonon transport mechanism. By contrast in the case of n graphene layers, the interfacial thermal resistance is more or less independent on the number of layers for 1 ≤ n ≤ 10, and is associated with ballistic phonon transport mechanism. We attribute the diffusive heat transfer mechanism across WSe{sub 2} sheets to abundant low frequency and low group velocity optical modes that carry most of the heat across the interface. By contrast, in graphene, acoustic modes dominate the thermal transport across the interface and render a ballistic heat flow mechanism.
- OSTI ID:
- 22273625
- Journal Information:
- Journal of Applied Physics, Vol. 115, Issue 14; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Spatiotemporal Observation of Quasi-Ballistic Transport of Electrons in Graphene
Thermal conductance enhanced via inelastic phonon transport by atomic vacancies at Cu/Si interfaces