LNESS and Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Milano, Italy.
Nanotechnology. 2017 Jan 27;28(4):045605. doi: 10.1088/1361-6528/28/4/045605. Epub 2016 Dec 20.
In As atmosphere, we analyzed the crystallization dynamics during post-growth annealing of Ga droplets residing at the top of self-assisted GaAs nanowires grown by molecular beam epitaxy. The final crystallization steps, fundamental to determining the top facet nanowire morphology, proceeded via a balance of Ga crystallization via vapor-liquid-solid and layer-by-layer growth around the droplet, promoted by Ga diffusion out of the droplet perimeter, As desorption, and diffusion dynamics. By controlling As flux and substrate temperature the transformation of Ga droplets into nanowire segments with a top surface flat and parallel to the substrate was achieved, thus opening the possibility to realize atomically sharp vertical heterostructures in III-As self-assisted nanowires through group III exchange.
在大气环境中，我们分析了通过分子束外延生长的自辅助 GaAs 纳米线顶端的 Ga 液滴在生长后退火过程中的结晶动力学。最终的结晶步骤对于确定纳米线顶端的面形态至关重要，其通过 Ga 通过汽-液-固过程结晶以及围绕液滴的逐层生长之间的平衡来实现，这一过程受到 Ga 从液滴边界扩散、As 解吸和扩散动力学的促进。通过控制 As 通量和衬底温度，可以将 Ga 液滴转化为具有与衬底平行且顶部表面平整的纳米线段，从而实现通过 III 族元素交换在 III-V 族自辅助纳米线中实现原子级锐利的垂直异质结构的可能性。
