Institute of Physical Chemistry, Bulgarian Academy of Sciences, 1113, Sofia, Bulgaria.
Nanoscale Res Lett. 2007 May 1;2(5):235-9. doi: 10.1007/s11671-007-9054-8.
The kinetics of nanowhiskers growth is studied theoretically taking into account the adatom diffusion from the surface to the top of needle. An exponential growth with time is expected for the initial stages of the process, when the lengthlof the whisker is smaller than the average diffusion length λ of adatoms. It transforms to linear growth rate forl > λ. The formation of nanotubes with a hollow core dislocation is explained by accounting for the role of the stress in the middle of screw dislocations. When the magnitude of the Burgers vector exceeds a critical value, it is energetically more favorable to remove the highly strained material around the dislocation line and to create a tube with an additional free surface. Additionally, there is an important size effect, due to the small radiusRof the nanowhisker. The interplay, between the contributions from the size effects and from the diffusion, explains why for the very thin nanowhiskers the lengthlis proportional to the radiusRwhile, otherwise the length is inversely proportional to it, i.e.,l∼1/R.
纳米线生长的动力学理论研究考虑了从表面到针顶端的原子扩散。在纳米线长度小于平均扩散长度 λ 的初始阶段，预计会出现指数增长。当 l > λ 时，它会转变为线性增长率。通过考虑螺位错中间的应力作用，解释了具有中空核心位错的纳米管的形成。当伯格斯矢量的大小超过临界值时，从位错线周围去除高应变材料并创建具有附加自由表面的管在能量上更为有利。此外，由于纳米线的半径 R 很小，还存在重要的尺寸效应。尺寸效应和扩散的共同作用解释了为什么对于非常细的纳米线，长度 l 与半径 R 成正比，而其他情况下，长度与半径 R 成反比，即 l∼1/R。
