Environmental Engineering Reference
In-Depth Information
Figure 5.5
Cross-sectional area dependent thermal conductivity for naked
SiNWs and H-SiNWs at 300 K (Left to right: 2.36 nm
2
,3.69nm
2
,and
5.31 nm
2
). Reprinted with permission from [43]. Copyright c
2012, City
University of Hong Kong.
where
k
B
isthe Boltzmann constant,and
J
z
(t) isthe z-componentof
heat current vector.
5.3 Surface Hydrogenation Effect on the Thermal
Conductivity of SiNWs
Simulations are preformed using different lengths of naked SiNWs
ranging from 2.72 nm to 8.68 nm, and the results show that
the longitudinal thermal conductivity becomes length-independent
when the naked SiNWs is longer than 6.52 nm, which corresponds
to 12 unit cells. Hydrogenation can induce slight increase in the
thermal conductivity, by 15-25% (Fig. 5.5) compared with that of
naked surface SiNWs. This phenomenon of hydrogenation induced
increase in the thermal conductivity can be correlated with their
structures and lattice vibration properties.
