Preparation of sharp gold tips for STM by using electrochemical etching method

Gold tips were obtained from gold wire (Au) with a diameter of 0.25 mm. They were produced by electrochemical etching technique using 0.8 M-97% KCN solution. Tips were etched by applying different voltages such as 8, 12, 16, 20 V, seperately. For each different applied voltage, some of tips were washed with the distilled water. The rest of them were not washed. SEM investigated tips and elemental analysis of the apex of the tip was studied by EDX. According to SEM and TEM images, the radius of tips was estimated. Tip radius varies between 200 and 500 nm. Small amounts of K (Potassium) and Cu (Copper) elements were observed on the surface of the tips after the electrochemical reaction. In addition to that, TEM and XRD characterized tips.