Hello,
I'm fabricating Au tip for STM/AFM probe by electrochemical etching. I found in a paper of David Gingery (2007) 'Single-step electrochemical method for producing very sharp Au scanning tunneling microscopy tips' a method to do Au-etching in (NaCl 3M, HClO4 1%) using graphite electrode and AC voltage. I would like to ask if there is any particular reason for using graphite instead of Pt/Ir (which fits better my set-up, and with Pt/Ir I can use a smaller voltage if I understand correctly). And the same question about the choice of AC/DC voltage (I would prefer DC voltage).
Best regards,
LE Tuan Nghia.
http://aip.scitation.org/doi/abs/10.1063/1.2804132
Dear Tuan
You can use graphite Pt/Ir rather than graphite as a counter electrode in the electrochemical cell of etching the Au tip. Normally, one would use graphite instead of Pt/Ir because graphite is much cheaper than Pt/Ir.
Also, the use of AC rather than the Dc for the electrochemical etching of the Au because AC is more subtle than DC , especially when it comes to remove mass in order to sharping the tip of the Au for the STM/AFM applications.
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