Thermal conductivity of copper films

The thermal conductivity of thin films of copper (400–8000 Å) has been measured in the temperature range 100–500 K. It decreases with decreasing film thickness. An electrical-thermal transport analogy has been used to calculate the size-dependent thermal conductivity of the thin copper films. The decrease of the thermal conductivity with thickness is attributed partly to the scattering of the conduction electrons from the film surfaces and partly to the scattering by lattice impurities and frozen-in structural defects in the films. The variation of the thermal conductivity with temperature agrees with the variation for bulk copper. The Lorentz ratio has been determined and is found to vary from 2.4 × 10^-8 to $\text{2.0 × 10}{}^{-8}\text{W}\text{Ω/}\text{deg}{}^2$ for film thicknesses ranging from 400 to 8000 Å.