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Electrochemical fabrication of silver tips for tip‐enhanced Raman spectroscopy assisted by a machine vision system
Author(s) -
Li Maohua,
Lv Ruiqi,
Huang Shengchao,
Dai Yinzhen,
Zeng Zhicong,
Wang Lei,
Ren Bin
Publication year - 2016
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4898
Subject(s) - raman spectroscopy , etching (microfabrication) , scanning tunneling microscope , materials science , radius of curvature , fabrication , nanoprobe , optoelectronics , nanotechnology , microscopy , optics , analytical chemistry (journal) , curvature , chemistry , nanoparticle , physics , medicine , mean curvature , geometry , mathematics , alternative medicine , layer (electronics) , mean curvature flow , pathology , chromatography
Both tip‐enhanced Raman spectroscopy and scanning tunneling microscopy require the use of sharp tips. Electrochemical etching appears to be the most widely used method for preparing tips. To address the over‐etching problem associated with the silver tips by either using voltage or current as a feedback, we developed here an optical method‐based machine vision to achieve a quick cutoff of the circuit once the tip forms. It is a fully automated method with a response time of about 40 ms and is tolerated with any existing electrochemical etching method. We can significantly decrease the time of over‐etching of the silver tip when short rectangular pulses with a duty cycle of 28.6% were used. The mean radius of curvature was ca. 58 nm, as measured from over 50 tips. The capacities of silver tips for high‐resolution scanning tunneling microscopy imaging and high‐sensitivity tip‐enhanced Raman studies have been demonstrated. Copyright © 2016 John Wiley & Sons, Ltd.