Tunable thermal conductivity of Si1-x Gex nanowires

Abstract

By using molecular dynamics simulation, we demonstrate that the thermal conductivity of silicon-germanium nanowires (Si1-x Gex NWs) depends on the composition remarkably. The thermal conductivity reaches the minimum, which is about 18% of that of pure Si NW, when Ge content is 50%. More interesting, with only 5% Ge atoms (Si0.95 Ge0.05 NW), SiNW's thermal conductivity is reduced to 50%. The reduction of thermal conductivity mainly comes from the localization of phonon modes due to random scattering. Our results demonstrate that Si1-x Gex NW might have promising application in thermoelectrics. © 2009 American Institute of Physics.