Phonon heat conduction in a semiconductor nanowire

A model for phonon heat conduction in a semiconductor nanowire with dimensi ons comparable to the phonon mean free path is developed. It is based on th e solution of Boltzmann's equation, which takes into account (i) modificati on of the acoustic phonon dispersion due to spatial confinement, and (ii) c hange in the nonequilibrium phonon distribution due to partially diffuse bo undary scattering. Numerical simulation is performed for a silicon nanowire with boundaries characterized by different interface roughness. Phonon con finement and boundary scattering lead to a significant decrease of the latt ice thermal conductivity. The value of this decrease and its interface roug hness and temperature dependence are different from the predictions of the early models. The observed change in thermal resistance has to be taken int o account in simulation of deep-submicron and nanometer-scale devices. (C) 2001 American Institute of Physics.