Surface diffusion is known to be of prime importance in the growth of semiconductor nanowires. In this work, we used ZnMgO layers as markers to analyze the growth mechanisms and kinetics during the deposition of ZnMgO/ZnO multilayered shells by molecular beam epitaxy on previously grown ZnO nanowire cores (so called core-shell heterostructures). Specifically, the influence of the O2 flow sent into the plasma cell on the adatom surface mobility was investigated. By carefully measuring the growth rate on the lateral facets as well as on the top of the nanowires, it is concluded that the surface diffusion length of adatoms, within the used MBE growth conditions, is very low. Such poor surface mobility explains why so few works can be found related to the spontaneous growth (without catalyst) of ZnO nanowires by MBE, contrary to other deposition techniques.

中文翻译：

---

为什么使用分子束外延法很难自发生长 ZnO 纳米线？

已知表面扩散在半导体纳米线的生长中是最重要的。在这项工作中，我们使用 ZnMgO 层作为标记来分析通过分子束外延在先前生长的 ZnO 纳米线核（所谓的核壳异质结构）上沉积 ZnMgO/ZnO 多层壳过程中的生长机制和动力学。具体而言，研究了进入等离子体池的 O2 流量对吸附原子表面迁移率的影响。通过仔细测量侧面以及纳米线顶部的生长速率，得出的结论是，在所使用的 MBE 生长条件下，吸附原子的表面扩散长度非常低。如此差的表面迁移率解释了为什么很少发现与 MBE 的 ZnO 纳米线自发生长（无催化剂）相关的工作，