Thermal conductivity reduction by 60{\deg} shuffle-set dislocation arrays embedded in silicon nano-films

Abstract

Based on the Debye-Callaway and the Klemens model, as well as molecular dynamics, the paper proposes mechanism of thermal conductivity reduction by embedding dense 60{\deg} shuffle-set dislocation arrays into silicon nano-films. Thermal conductivity reduction to 2% of that of bulk silicon has been obtained. The reduction is found mainly due to longitudinal phonon scattering at the dislocation cores, where the scattering rate is stronger than that presented by Klemens. Within an effective diameter of about 9 nm around their cores, the dislocations locally scatter phonons, resulting in a dramatical density-dependent reduction of thermal conductivity for a dislocation density larger than 10^14 m^-2.