Tuning the thermal conductivity of silicon nanowires (Si-NWs) is essential for realization of future thermoelectric devices. The corresponding management of thermal transport is strongly related to the scattering of phonons, which are the primary heat carriers in Si-NWs. Using the molecular dynamics method, we find that the scattering of phonons from internal body defects is stronger than that from surface structures in the low-porosity range. Based on our simulations, we propose the concept of an exponential decay in thermal conductivity with porosity, specifically in the low-porosity range. In contrast, the thermal conductivity of Si-NWs with a higher porosity approaches the amorphous limit, and is insensitive to specific phonon scattering processes. Our findings contribute to a better understanding of the tuning of thermal conductivity in Si-NWs by means of patterned nanostructures, and may provide valuable insights into the optimal design of one-dimensional thermoelectric materials.

调整硅纳米线（Si-NWs）的热导率对于实现未来的热电设备至关重要。热传输的相应管理与声子的散射密切相关，声子是Si-NWs中的主要载热体。使用分子动力学方法，我们发现在低孔隙率范围内，来自内部缺陷的声子的散射要强于来自表面结构的声子的散射。根据我们的模拟，我们提出了导热系数随孔隙率（特别是在低孔隙率范围内）呈指数衰减的概念。相反，具有较高孔隙率的Si-NW的热导率接近非晶极限，并且对特定的声子散射过程不敏感。