Heat transfer across nanoscale metal/dielectric multilayers involves multiple thermal conduction mechanisms. Electron or phonon interface scattering can augment the thermal conductivity anisotropy in multilayer composites. Weak electron-phonon coupling and quasi-ballistic phonon transport normal to the metal film further increase the anisotropy for metal-dielectric multilayers with period shorter than the relevant free paths. This paper models these physical mechanisms using an approximate thermal resistor network with support from the Boltzmann transport equation. We measure the in- and cross-plane thermal conductivity of a Mo/Si (2.8 nm/4.1 nm) multilayer as 15.4 and 1.2 W/mK, respectively, which agree with the proposed theoretical model. This work introduces a criterion for the transition from electron to phonon dominated heat conduction in metal films bounded by dielectrics.
- Heat Transfer Division
Electron-Phonon Coupled Two-Dimensional Heat Transfer in Nanoscale Metal/Dielectric Multilayers
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Li, Z, Tan, S, Kodama, T, Bozorg-Grayeli, E, Asheghi, M, & Goodson, KE. "Electron-Phonon Coupled Two-Dimensional Heat Transfer in Nanoscale Metal/Dielectric Multilayers." Proceedings of the ASME 2012 Heat Transfer Summer Conference collocated with the ASME 2012 Fluids Engineering Division Summer Meeting and the ASME 2012 10th International Conference on Nanochannels, Microchannels, and Minichannels. Volume 1: Heat Transfer in Energy Systems; Theory and Fundamental Research; Aerospace Heat Transfer; Gas Turbine Heat Transfer; Transport Phenomena in Materials Processing and Manufacturing; Heat and Mass Transfer in Biotechnology; Environmental Heat Transfer; Visualization of Heat Transfer; Education and Future Directions in Heat Transfer. Rio Grande, Puerto Rico, USA. July 8–12, 2012. pp. 579-587. ASME. https://doi.org/10.1115/HT2012-58350
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