Metal-assisted chemical etching (MaCE), a low-cost and versatile method was considered a promising technique for preparing silicon nanowires (SiNWs), yet the lack of well controlling the injected holes within Si might reduce the etching rate, create the unwanted sidewall etching, and degrade the structural uniformity. Herein, in this study, the bias-modulated MaCE process was performed, showing the etching rates more than four times of magnitude than that of typical bias-free MaCE with large-area uniformity. It was found that the field-mediated hole rectification overwhelmed the effect of retarded diffusivity from reactive ions, and thus the dynamics of distributed etching were therefore transferred to the directional etching behaviors. In addition, the etching orientation could be also manipulated with the external bias. The results demonstrated that the etching direction was switched toward the slanted features by varying the electric polarization, creating the special slanted/vertical NW arrays, which possessed the superior antireflection characteristics than the conventional vertically aligned features.

中文翻译：

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电场辅助硅纳米线阵列的高速、方向控制形成。


金属辅助化学蚀刻（MaCE）是一种低成本且通用的方法，被认为是一种有前途的制备硅纳米线（SiNW）的技术，但缺乏对硅内注入孔的良好控制可能会降低蚀刻速率，产生不需要的侧壁蚀刻，并降低结构的均匀性。在这项研究中，进行了偏压调制的 MaCE 工艺，其蚀刻速率比典型的无偏压 MaCE 的蚀刻速率高出四倍以上，且具有大面积均匀性。研究发现，场介导的空穴校正压倒了反应离子的延迟扩散率的影响，因此分布式蚀刻的动力学因此转移到定向蚀刻行为。此外，蚀刻方向也可以通过外部偏压来控制。结果表明，通过改变电极化，蚀刻方向转向倾斜特征，形成特殊的倾斜/垂直纳米线阵列，其具有比传统垂直排列特征更优异的抗反射特性。