We have developed the automatic shutdown system of the alternate-current (AC) etching for fabricating platinum/irridium (Pt/Ir) tips used for scanning tunneling microscope (STM). Potassium chroride solution was used for the AC etching. We modified the electronic circuit used for the direct-current (DC) electrochemical etching of tungsten tips, by inserting (1) AC sensing coil, (2) double voltage rectifier circuit for the conversion of AC signal to DC, and (3) the relay for the AC electrochemical etching circuit. Schmitt trigger circuit was also imposed between the signal comparizon circuit and the switching field-effective transistor (FET). Moerover, DC currents were applied before and after the electrochemical etching in order to remove the contaminants and by-product of platinum chrorides. Here we show how it works and the results of the fabrication of Pt/Ir tips.

Development of automatic alternate-current electrochemical etching system for the platinum/irridium probe of scanning tunneling microscopy

2019 Spring National Meeting

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