Abstract: Molecular dynamics (MD) simulations are performed to study the composition-dependent elastic modulus
and thermal conductivity for carbon/silicon core/shell nanowires (NWs). For each concerned carbon/silicon
core/shell NW with a specified diameter, it is found that elastic modulus is reduced with a linear dependence
on cross-sectional area ratio. The fact matches well with the results of theoretical model. Analysis based on
the cross-sectional stress distribution indicates that the core region of core/shell NW is capable of functioning as
a mechanical support. On the other hand, thermal conductivity also relies on the cross-sectional area ratio of
amorphous silicon shell. The core/shell interface plays a considerable influence on the thermal transport property.
The decreasing rate of thermal conductivity is gradually decreased as the composition of amorphous silicon shell
increases. In addition, by calculating the phonon density of state, we demonstrate that the reduction in thermal
conductivity of the core/shell NW stems from the increase of the low frequency modes and the depression of
high-frequency nonpropagating diffusion modes. These results provide an effective way to modify the properties
of core/shell NWs for related application.
JING Yu-hanga,b* (荆宇航), YU Kai-pinga (于开平), QIN Xiana (覃弦), SHEN Junb* (沈军)
. Composition-Dependent Mechanical and Thermal Transport Properties of Carbon/Silicon Core/Shell Nanowires[J]. Journal of Shanghai Jiaotong University(Science), 2012
, 17(6)
: 743
-747
.
DOI: 10.1007/s12204-012-1357-y
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