High-Speed and Direction-Controlled Formation of Silicon Nanowire Arrays Assisted by Electric Field

• Published in: Nanoscale research letters 2020-01, Vol.15 (1), p.25-25, Article 25
• Main Authors: Chien, Pin-Ju, Wei, Ta-Cheng, Chen, Chia-Yun
• Format: Article
• Language: English
• Subjects: Arrays; Bias; Chemical etching; Chemistry and Materials Science; Electric fields; Electric polarization; Etching; Etching of Si; Formation mechanism; Materials Science; Molecular Medicine; Nano Express; Nanochemistry; Nanoscale Science and Technology; Nanotechnology; Nanotechnology and Microengineering; Nanowires; Organic chemistry; Reflectivity; Silicon; Surface wettability
• ISSN: 1931-7573; 1556-276X
• DOI: 10.1186/s11671-020-3259-5

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.