Instituto de Física Gleb Wataghin, Universidade Estadual de Campinas, UNICAMP, 13083-859, Campinas, SP, Brazil.
Nano Lett. 2013 Jan 9;13(1):9-13. doi: 10.1021/nl302891b. Epub 2012 Dec 6.
We have observed that thin InP nanowires generated by vapor-liquid-solid growth display spontaneous periodic diameter oscillations when large group III supersaturations are used. Diameter variations are associated with a large number of stacking faults and crystallographic phase changes(wurtzite/zinc-blende); also the axial distance between oscillations depends on the indium precursor flow used during the run. We attribute the morphology changes to a substantial deformation of the triple phase line (vapor-liquid-solid) at the catalyst nanoparticle edge originated from multistep nucleation during growth. The deformation alters the mechanical force balance acting on the nanoparticle during growth in such a way that the particle displaces from the nanowire top and wets the nanowire sidewall. Subsequently, as catalytic growth occurs at the sidewall, the associated increase in diameter will eventually push the NP back to its original wire-top position until the onset of a new instability at the triple phase line.
我们观察到，使用大的 III 族过饱和度时，由气-液-固生长产生的薄 InP 纳米线会自发地产生周期性的直径振荡。直径变化与大量的位错和结晶相变化（纤锌矿/闪锌矿）有关；此外，振荡之间的轴向距离取决于运行过程中使用的铟前体流量。我们将形态变化归因于催化剂纳米颗粒边缘的三相线（气-液-固）的大幅度变形，这种变形源于生长过程中的多步形核。这种变形改变了作用在生长过程中的纳米颗粒上的机械力平衡，使得颗粒从纳米线的顶部位移并润湿纳米线的侧壁。随后，当在侧壁上发生催化生长时，直径的相应增加最终将 NP 推回到其原始的线顶位置，直到三相线处出现新的不稳定性。
