School of Physics and the Australian Institute for Nanoscale Science and Technology, The University of Sydney, 2006, Sydney, Australia.
Department of Electronic Materials Engineering, The Australian National University, 2601, Canberra, Australia.
Adv Mater. 2017 Aug;29(31). doi: 10.1002/adma.201701888. Epub 2017 Jun 19.
III-V ternary InGaAs nanowires have great potential for electronic and optoelectronic device applications; however, the 3D structure and chemistry at the atomic-scale inside the nanowires remain unclear, which hinders tailoring the nanowires for specific applications. Here, atom probe tomography is used in conjunction with a first-principles simulation to investigate the 3D structure and chemistry of InGaAs nanowires, and reveals i) the nanowires form a spontaneous core-shell structure with a Ga-enriched core and an In-enriched shell, due to different growth mechanisms in the axial and lateral directions; ii) the shape of the core evolves from hexagon into Reuleaux triangle and grows larger, which results from In outward and Ga inward interdiffusion occurring at the core-shell interface; and iii) the irregular hexagonal shell manifests an anisotropic growth rate on {112}A and {112}B facets. Accordingly, a model in terms of the core-shell shape and chemistry evolution is proposed, which provides fresh insights into the growth of these nanowires.
III-V 三元合金 InGaAs 纳米线在电子和光电子器件应用方面具有巨大潜力；然而，纳米线内部的三维结构和原子尺度上的化学性质仍不清楚，这阻碍了为特定应用定制纳米线。在这里，原子探针层析技术与第一性原理模拟相结合，用于研究 InGaAs 纳米线的三维结构和化学性质，揭示了：i）由于轴向和横向生长机制不同，纳米线形成了富 Ga 核和富 In 壳的自发核壳结构；ii）由于核壳界面处发生的 In 向外和 Ga 向内互扩散，核的形状从六边形演变为 Reuleaux 三角形并变大；iii）不规则的六边形壳在{112}A 和{112}B 晶面上表现出各向异性的生长速率。因此，提出了一个关于核壳形状和化学演变的模型，为这些纳米线的生长提供了新的见解。
