Electrodeposited Gold Probe for Electrochemical Scanning Tunneling Microscopy
Yuzu Kobayashi, Yasuyuki Yokota, Yasufumi Takahashi, Jun Takeya, Yousoo Kim
Abstract
Direct measurements at the solid–liquid interface on the nanometer scale provide information about various physical and chemical processes from both fundamental and applied aspects. Electrochemical scanning tunneling microscopy (EC-STM) is a powerful tool that makes it possible to perform STM measurements at the solid–liquid interfaces. However, EC-STM remains challenging due to the difficulty of fabricating the probe for tunneling current measurements in solutions. In this study, we established a novel and versatile method to easily fabricate the EC-STM probe with high reproducibility. By electrochemically depositing Au on a pyrolytic carbon formed within the glass nanopipette which has an aperture of several hundred nanometers, we achieved a sufficient insulation with almost 100% probability, which overcomes the 30-year challenge of previous EC-STM studies. High-quality EC-STM images could be stably obtained with a yield of >80% using the probe. It will pave the way for future advanced measurements at a variety of solid–liquid interfaces, such as single molecule spectroscopy and electronic structure characterizations.