We propose to reduce the thermal conductivity of silicon nanowires (SiNWs) by introducing small hole at the centre, i.e. construct silicon nanotube (SiNT) structures. Our numerical results demonstrate that a very small hole (only 1% reduction in cross section area) can induce a 35% reduction in room temperature thermal conductivity. Moreover, with the same cross section area, thermal conductivity of SiNT is only about 33% of that of SiNW at room temperature. The spatial distribution of vibrational energy reveals that localization modes are concentrated on the inner and outer surfaces of SiNTs. The enhanced surface-to-volume ratio in SiNTs reduces the percentage of delocalized modes, which is believed to be responsible for the reduction of thermal conductivity. Our study suggests SiNT is a promising thermoelectric material with low thermal conductivity.
@article{arxiv.1010.2861,
title = {Remarkable Reduction of Thermal Conductivity in Silicon Nanotubes},
author = {Jie Chen and Gang Zhang and Baowen Li},
journal= {arXiv preprint arXiv:1010.2861},
year = {2015}
}