Metallic electrode pairs with angstrom or nano-scale gap play a key role in studying the electron transport in molecular electronic and nano-electronic devices. Here we report a novel method of electrochemical etching to prepare gold electrode pairs. By adjusting the parameter of the homemade feedback loop and the etching voltage,a series of electrode pairs with different sizes of gap were fabricated. The process is simple and dispenses with special equipments. This method also has the potential for fabricating other metallic electrode pair with a controlled gap distance.
