Remarkable Reduction of Thermal Conductivity in Silicon Nanotubes

We propose to reduce the thermal conductivity of silicon nanowires (SiNWs) by introducing a small hole at the center. i e, construct a silicon nanotube (SiNT) structure 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