Thermal Conductivity of Thin Metallic Films

This study examines the effect of transverse thickness on the in-plane thermal conductivity of single crystal, defect-free, thin metallic films. The imposed temperature gradient is along the film and the transport of thermal energy is predominantly due to free electron motion. The small size necessitates an evaluation of the Boltzmann equation of electron transport along with appropriate electron scattering boundary conditions. Simple expressions for the reduction of conductivity due to increased dominance of boundary scattering are presented and the results are compared with other simplified approaches and experimental data from the literature. Grain boundary scattering is also considered via simple arguments.