TY - JOUR
T1 - Fundamental insight into control of thermal conductivity in silicon-germanium alloy nanowires
AU - Lee, Yongjin
AU - Hwang, Gyeong S.
N1 - Publisher Copyright:
Copyright © 2014 Materials Research Society.
PY - 2014
Y1 - 2014
N2 - We present a computational analysis of thermal transport in Silicon-Germanium alloy nanowires (SiGeNWs), particularly focusing on the relative roles of alloy scattering and boundary scattering to the significant reduction of thermal conductivity (κ). Our nonequilibrium molecular dynamics (NEMD) simulations confirm the strong dependence of κ on Si:Ge ratio, as observed in previous experimental studies. Interestingly, as the amount of impurity increases, the difference in κ between SiGe bulk and SiGeNW becomes smaller. Especially, κSiGeNW and κSiGe have similar κ values when the Ge content is 20-80 %. From a nonequilibrium Green's function (NEGF)-density functional theory (DFT) analysis, it is suggested that the most reduction in transmission channels is attributed to the strong alloy scattering effect for both Si0.8Ge0.2 bulk and Si0.8Ge0.2 NW. The boundary scattering effect in the SiGe alloy system seems to be unimportant as alloy scattering is dominant. The improved understanding provides fundamental insight into how to modify Si-based materials to enhance their thermoelectric (TE) properties through nanostructuring and alloying.
AB - We present a computational analysis of thermal transport in Silicon-Germanium alloy nanowires (SiGeNWs), particularly focusing on the relative roles of alloy scattering and boundary scattering to the significant reduction of thermal conductivity (κ). Our nonequilibrium molecular dynamics (NEMD) simulations confirm the strong dependence of κ on Si:Ge ratio, as observed in previous experimental studies. Interestingly, as the amount of impurity increases, the difference in κ between SiGe bulk and SiGeNW becomes smaller. Especially, κSiGeNW and κSiGe have similar κ values when the Ge content is 20-80 %. From a nonequilibrium Green's function (NEGF)-density functional theory (DFT) analysis, it is suggested that the most reduction in transmission channels is attributed to the strong alloy scattering effect for both Si0.8Ge0.2 bulk and Si0.8Ge0.2 NW. The boundary scattering effect in the SiGe alloy system seems to be unimportant as alloy scattering is dominant. The improved understanding provides fundamental insight into how to modify Si-based materials to enhance their thermoelectric (TE) properties through nanostructuring and alloying.
KW - simulation
KW - thermal conductivity
KW - thermoelectric
UR - http://www.scopus.com/inward/record.url?scp=84926375698&partnerID=8YFLogxK
U2 - 10.1557/opl.2014.665
DO - 10.1557/opl.2014.665
M3 - Conference article
AN - SCOPUS:84926375698
SN - 0272-9172
VL - 1707
JO - Materials Research Society Symposium - Proceedings
JF - Materials Research Society Symposium - Proceedings
Y2 - 21 April 2014 through 25 April 2014
ER -