Arif Omer, Zannier Valentina, Dubrovskii Vladimir G, Shtrom Igor V, Rossi Francesca, Beltram Fabio, Sorba Lucia
NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, Piazza San Silvestro 12, I-56127 Pisa, Italy.
School of Photonics, ITMO University, Kronverkskiy pr. 49, 197101 St. Petersburg, Russia.
Nanomaterials (Basel). 2020 Mar 10;10(3):494. doi: 10.3390/nano10030494.
The growth mechanisms of self-catalyzed InAs/InSb axial nanowire heterostructures are thoroughly investigated as a function of the In and Sb line pressures and growth time. Some interesting phenomena are observed and analyzed. In particular, the presence of In droplet on top of InSb segment is shown to be essential for forming axial heterostructures in the self-catalyzed vapor-liquid-solid mode. Axial versus radial growth rates of InSb segment are investigated under different growth conditions and described within a dedicated model containing no free parameters. It is shown that widening of InSb segment with respect to InAs stem is controlled by the vapor-solid growth on the nanowire sidewalls rather than by the droplet swelling. The In droplet can even shrink smaller than the nanowire facet under Sb-rich conditions. These results shed more light on the growth mechanisms of self-catalyzed heterostructures and give clear route for engineering the morphology of InAs/InSb axial nanowire heterostructures for different applications.
对自催化InAs/InSb轴向纳米线异质结构的生长机制进行了深入研究，该机制是In和Sb线压力以及生长时间的函数。观察并分析了一些有趣的现象。特别地，InSb段顶部In液滴的存在被证明对于在自催化气-液-固模式下形成轴向异质结构至关重要。在不同生长条件下研究了InSb段的轴向与径向生长速率，并在一个不含自由参数的专用模型中进行了描述。结果表明，InSb段相对于InAs茎的加宽是由纳米线侧壁上的气-固生长控制的，而不是由液滴膨胀控制的。在富Sb条件下，In液滴甚至可以收缩到比纳米线小面还小。这些结果为自催化异质结构的生长机制提供了更多的见解，并为针对不同应用设计InAs/InSb轴向纳米线异质结构的形态提供了明确的途径。
