Abstract
From the perspective of maximizing the practicability of tungsten nano-tips, a sharp tip, long taper, and large shank are usually expected. However, simultaneously satisfying the requirements for tip radius, taper length, and shank diameter is theoretically impossible with the conventional drop-off tip fabrication method, which is based on lamellae electrochemical etching. In this study, a two-step etching method is proposed to fabricate a sub-10-nm tungsten tip directly from a 1-mm rod. First, a floating electrolyte-based drop-off process is carried out to fabricate a tungsten needle with a long length taper of 10 mm. Then, an inversed lamellae drop-off process is conducted to realize fine etching of the needlepoint. As a result, an ultra-sharp tungsten nano-tip with a radius of 5.5 nm and taper length of 10 mm is successfully fabricated from a 1-mm tungsten rod.
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Acknowledgements
This work was financially supported by the research fund for Basic Research (Free Exploration: JCYJ20180302174311087) and the research fund for International Cooperation from the Science and Technology Innovation Committee of Shenzhen Municipality (GJHZ20180928155412525 and GJHZ20180411143558312).
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Qin, S., Deng, H. Electrochemical Etching of Tungsten for Fabrication of Sub-10-nm Tips with a Long Taper and a Large Shank. Nanomanuf Metrol 2, 235–240 (2019). https://doi.org/10.1007/s41871-019-00050-6
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DOI: https://doi.org/10.1007/s41871-019-00050-6