Multiple radial phosphorus segregations in GaAsP core-shell nanowires
Multiple radial phosphorus segregations in GaAsP core-shell nanowires
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DOI：
10.1007/s12274-020-3060-x
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发表时间：
2020-09
期刊：
影响因子：
9.9
通讯作者：
H. Fonseka;Yunyan Zhang;James A. Gott;R. Beanland;Huiyun Liu;A. Sánchez
中科院分区：
文献类型：
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作者：
H. Fonseka;Yunyan Zhang;James A. Gott;R. Beanland;Huiyun Liu;A. Sánchez
高度多面几何形状，如纳米线，容易形成自形成的特征，特别是那些由分离驱动的特征。了解这些特征对于防止它们形成、了解它们对纳米线性能的影响或设计应用非常重要。在合金半导体纳米线中，沿六角形截面半径运行的单元素偏析线是常见的观察结果。这里，在GaAsP纳米线中，在主带的两侧形成了两个额外的富P带，导致在三个交替半径附近共有三个偏析带。这些条带的强度低于原始条带，它们的形成可归因于在顶点附近形成的倾斜纳米面。次级带的形成需要更高的壳中P的组成，并且需要在增大As和P之间扩散系数差的条件下生长。此外，观察到初级带可以分裂成两个狭窄的平行带。这可以发生在所有六个半径，使截面最多有18个径向偏析带。通过控制生长，这些特性可以在纳米线内以新的维度（周向）组装多个不同的量子结构。
Highly faceted geometries such as nanowires are prone to form self-formed features, especially those that are driven by segregation. Understanding these features is important in preventing their formation, understanding their effects on nanowire properties, or engineering them for applications. Single elemental segregation lines that run along the radii of the hexagonal cross-section have been a common observation in alloy semiconductor nanowires. Here, in GaAsP nanowires, two additional P rich bands are formed on either side of the primary band, resulting in a total of three segregation bands in the vicinity of three of the alternating radii. These bands are less intense than the primary band and their formation can be attributed to the inclined nanofacets that form in the vicinity of the vertices. The formation of the secondary bands requires a higher composition of P in the shell, and to be grown under conditions that increase the diffusivity difference between As and P. Furthermore, it is observed that the primary band can split into two narrow and parallel bands. This can take place in all six radii, making the cross sections to have up to a maximum of 18 radial segregation bands. With controlled growth, these features could be exploited to assemble multiple different quantum structures in a new dimension (circumferential direction) within nanowires.