Experimental Study on Thermal Property of Nanowires

以碳纳米管（CNT）为代表的纳米线的热输运取决于其原子结构和尺寸。本研究分别测量了纳米线的热导率，并与纳米线的原子结构进行了比较。采用定制的纳米热传感器对多壁碳纳米管、碳化硅纳米线和杯状碳纳米纤维进行处理。由于与一维谐波链结构相似，cscnf具有弹道声子输运特性。通过分子动力学模拟验证了这一实验，并探讨了准一维体系的传热机理。由于外表面声子散射，SiC纳米线的导热系数远低于体材。首次成功地定量测量了碳纳米管与固体表面之间的热边界阻。本研究加深了我们对纳米材料热输运的认识。

Thermal transport of nanowires represented by carbon nanotube (CNT) depends on their atomic structure and size. In this study, thermal conductivity of nanowire was measured individually and discussed in comparison with its atomistic structure using HRTEM. Multiwalled CNTs, SiC nanowires and cup-stacked carbon nano fibers (CSCNFs) were treated by using tailor-made nano thermal sensors. CSCNFs showed ballistic phonon transport due to their structural similarity with one-dimensional (1D) harmonic chain. Molecular dynamics simulations were used to confirm this experiment and investigate the mechanism of heat transfer in this quasi-1D system. The thermal conductivity of SiC nanowire was found much lower than that of bulk material due to the phonon scattering on the outer surface. Quantitative measurement of thermal boundary resistance between carbon nanotube and solid surface was also successfully conducted for the first time. This study deepened our understanding of thermal transport of nano materials.