碳纳米管包裹的硅纳米线复合结构的热稳定性研究

采用经典分子动力学方法模拟一定直径111]晶向的硅纳米线填充不同扶手椅型单壁碳纳米管复合结构的加热过程, 通过可视化和能量分析的方法判断复合结构中硅纳米线和碳纳米管的热稳定性. 通过讨论碳纳米管的空间限制作用和分子间相互作用力的关系, 对碳纳米管和硅纳米线的热稳定性变化进行初步解释. 研究发现碳纳米管中硅纳米线的热稳定性和碳纳米管的直径关系密切: 当管径较小时, 硅纳米线的热稳定性有所提高, 当管径增大到一定大小时, 硅纳米线的热稳定性会突然显著地下降, 直到硅纳米线与管壁不存在分子间相互作用力, 硅纳米线的热稳定性才会恢复. 而硅纳米线填充到碳纳米管中对碳纳米管的热稳定性有着明显的降低作用.

Thermal stability of compound stucture of silicon nanowire encapsulated in carbon nanotubes

To guide the experiment research, the thermal stability of composite silicon nanowire encapsulated in carbon nanotubes is investigated by computer simulation. The cubic-diamond-structured silicon nanowires with the same diameter and 111] orientationt are filled in some armchaired single-walled carbon nanotubes. The heat process of compound structure of silicon nanowire encapsulated in carbon nanotubes is simulated by classical molecular dynamic method. Through the visualization and energy analysis method, the thermal stability of composite structure is studied. The changes in the thermal stability of silicon nanowires and carbon nanotubes are explained by the relationship between carbon nanotube space constraint and van der Waals force. It is found that the diameter of the carbon nanotubes is closely related to the thermal stability of silicon nanowires inside. When the nanotube diameter is small, thermal stability of silicon nanowires increases; when the nanotube diameter increases up to a certain size, the thermal stability of silicon nanowires will suddenly drop significantly: until the distance between silicon nanowires and the wall of carbon nanotube is greater than 1 nm, the thermal stability of silicon nanowires will be restored. On the other hand, silicon nanowires filled into the carbon nanotubes have an effect of reducing the thermal stability of carbon nanotubes.