The thermal conductivities of 1μm copper-niobium multilayer films of different period thicknesses are measured by time–domain thermoreflectance at room temperature. The values for thermal conductivity are then used to calculate the thermal conductance between Cu/Nb interfaces using a series resistors model. Results show that Cu/Nb interface conductance increases with the decrease in period thickness reaching a value as high as 20 GWm−2K−1 for a 1×1 Cu/Nb multilayer. At shorter period thicknesses, ballistic electron transport dominates the thermal transport across this interface resulting in high interface conductance. The results are well described by a model that accounts for both ballistic and diffusive transport of electrons. This model assumes that an electron on one side of a metal-metal multilayer may not scatter at the interface but rather move ballistically on to the adjacent material and scatter in the adjacent material.
- Heat Transfer Division
The Effect of Ballistic Electron Transport on Copper-Niobium Thermal Interface Conductance
Cheaito, R, Duda, JC, Beechem, TE, Ihlefeld, JF, Hattar, K, Piekos, ES, Misra, A, Baldwin, JK, & Hopkins, PE. "The Effect of Ballistic Electron Transport on Copper-Niobium Thermal Interface Conductance." Proceedings of the ASME 2013 Heat Transfer Summer Conference collocated with the ASME 2013 7th International Conference on Energy Sustainability and the ASME 2013 11th International Conference on Fuel Cell Science, Engineering and Technology. Volume 1: Heat Transfer in Energy Systems; Thermophysical Properties; Theory and Fundamental Research in Heat Transfer. Minneapolis, Minnesota, USA. July 14–19, 2013. V001T03A009. ASME. https://doi.org/10.1115/HT2013-17541
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