Electrochemical fabrication of atomically thin metallic wires and electrodes separated with molecular-scale gaps

A Controllable Electrochemical Fabrication of Metallic Electrodes with a Nanometer/Angstrom‐Sized Gap Using an Electric Double Layer as Feedback

“…The second step is to narrow the gap down to the nanometer scale by electrodepositing Au atoms onto the working electrode. In comparison with previous methods [14][15][16][17][18][19] the present method has two major differences, namely, the electrode configuration and the feedback mode (see Figure 1). In our new design, the pair of facing electrodes serve as the working electrode (WE) and reference electrode (RE), respectively.…”

“…[14][15][16][17][18][19] By electrodepositing metal atoms onto a specific face of electrodes, one can sequentially narrow the gap from the original micrometer scale down to the domain of a few angstroms, or even connect two electrodes to form a quantum contact. [14][15][16][17][18][19] This electrochemical method is more versatile than the break-junction and electromigration methods mentioned above, especially as the process can be reversed in the electrodissolution mode for controlled etching of metal atoms from a wire to solution, thus widening the gap from angstrom up to sub-micrometer scales. The most important feature of the electrochemical method is the use of a feedback system to precisely control the resultant gap width.…”

Nanogap Electrodes

“…The feedback signal, taking an electroplating method as an example, is frequently the current flowing through the gap electrodes, which is monitored during the deposition process. [35,[59][60][61][62][63][64][65][66] When the electrodes are very close but not yet touching, the monitor current is extremely sensitive to electrode distance, so it is easy to control the separation on an atomic scale by stopping the electrodeposition process at predefined conductance values. Unlike a current-feedback mode that uses both facing electrodes as a working electrode (WE), Tian et al [58] invented a method for the controllable electrochemical fabrication of electrodes with a nanometer/angstrom-sized gap using the potential distribution in the electric double layer as feedback, wherein two facing electrodes served as the working electrode and reference electrode (RE), respectively.…”

A Nano-Transistor Based on Gate-Induced Thermal Switching

“…This has been shown (Urban et al, 2004b) to be the case for wires of conductance between a few and about a hundred conductance quanta for monovalent metals. Such nanowires with lengths below or around a few nanometers have been fabricated using various techniques, including scanning tunneling microscopy (STM, Agraït et al, 1993, Rubio et al, 1996, MCBJ (Yanson et al, 1998(Yanson et al, , 1999, thin-film transmission electron microscopy (TEM, Takayanagi, 1997, 2000), electromigration (Strachan et al, 2005), and electrochemical fabrication (He et al, 2002b). Nanowires with diameters less than a nanometer have been observed using TEM by Kondo and Takayanagi (1997) to be stable under low electron beam intensities for the duration of observation.…”