A double-electrolyte etching method of high-quality tungsten probe for undergraduate scanning tunneling microscopy and atomic force microscopy experiments

We have developed a double-electrolyte etching method to prepare sharp tungsten probes for scanning tunneling microscopy and atomic force microscopy. With the proposed etching method, high-quality tungsten probes can be produced. Furthermore, its simple implementation and easy operability significantly reduces the difficulty for operators and makes it tractable for amateur students. The method can achieve automatic cut off of the current as soon as tip formation occurs without using a cut-off circuit or microcontroller, which reduces the implementation cost and complexity. This is an effective way for students to prepare eligible tungsten probes in undergraduate scanning tunneling microscopy and atomic force microscopy experiments.