The thermal conductivities of Si1-x Gex nanowires (NWs) synthesized with Ge concentrations of 0.0%, 0.4%, 4%, and 9% and different diameters were measured from 40 to 420 K. The thermal conductivity of Si 1-x Gex NWs decreases as the Ge concentration increases due to alloy scattering. As the diameter of the Si1-x Gex NWs decreases, the thermal conductivity decreases due to phonon boundary scattering. However, the thermal conductivity dependency on the diameter of the NWs is not significant. This indicates that alloy scattering should be the dominant scattering mechanism in Si1-x Gex NWs. This study should provide a basis for designing efficient thermoelectric devices out of Si1-x Gex NWs and Si1-x Gex nanocomposites.
Bibliographical noteFunding Information:
Hyoungjoon Kim and Ilsoo Kim contributed equally to this paper. W.K. thanks Arun Majumdar, Renkun Chen, and Kedar Hippalgaonkar at U.C. Berkeley for providing the MEMS devices for thermal conductivity measurements and for useful discussions. This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (Grant Nos. KRF-2009-314-C00107, 2009K000452, and 2008-0058653/2009-0058653) and Seoul Research and Business Development Program (Program No. ST090859). H.C. acknowledges support from the National Research Laboratory program (Program No. R0A-2007-000-20075-0) and the Pioneer Research Program (Program No. 2009-008-1529) for converging technology through the Korea Science and Engineering Foundation funded by the Ministry of Education, Science and Technology.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)