Electron effective mean free path and thermal conductivity predictions of metallic thin films

A simple model of the electron effective mean free path (MFP) in thin metal films is proposed, and the thermal conductivities of aluminum and copper thin films are calculated by solving the Boltzmann transport equation (BTE). In the modeling of the electron effective MFP, the combined contributions of the bulk MFP and the film MFP are taken into account. The proposed effective electron MFP model is incorporated with the gray version of BTE through the "transport" relaxation time. The present model is verified against the experimental thermal conductivity data as a function of the film thickness.