Conductance histogram evolution of an EC–MCBJ fabricated Au atomic point contact

Abstract

This work presents a study of Au conductance quantization based on a combined electrochemical deposition and mechanically controllable break junction (MCBJ) method. We describe the microfabrication process and discuss improved features of our microchip structure compared to the previous one. The improved structure prolongs the available life of the microchip and also increases the success rate of the MCBJ experiment. Stepwise changes in the current were observed at the last stage of atomic point contact breakdown and conductance histograms were constructed. The evolution of 1G0 peak height in conductance histograms was used to investigate the probability of formation of an atomic point contact. It has been shown that the success rate in forming an atomic point contact can be improved by decreasing the stretching speed and the degree that the two electrodes are brought into contact. The repeated breakdown and formation over thousands of cycles led to a distinctive increase of 1G0 peak height in the conductance histograms, and this increased probability of forming a single atomic point contact is discussed.

An electrochemically assisted mechanically controllable break junction approach for single molecule junction conductance measurements

“…The potential difference between the working electrode (WE) and the reference electrode (RE) was monitored during the electrodeposition process. The electrodeposition process was stopped when the potential difference reached 0 V, indicating a nanometer scale contact had formed between the two electrodes [21]. Figure 1(b) shows the experimental setup for electrodeposition in a current controlled mode, and Fig.…”

“…Electrochemical deposition/dissolution has also been used to fabricate nanowires [18,19], and since it is much cheaper and faster than e-beam lithography, this method is an excellent candidate for combination with MCBJ. Previously, we have reported an electrochemically assisted MCBJ approach (EC-MCBJ) to fabricate nanogaps [20], create gold atomic point contacts [21], and measure the current-voltage (I-V) curves of probe molecules [22]. In our EC-MCBJ method, we fabricate electrode pairs with nanometer scale contact on a chip by optical lithography combined with galvanostatic electrodeposition.…”

Plasmonic Nanogaps: From Fabrications to Optical Applications

“…c) The side view of the electrode pair fabricated by electrochemically assisted MCBJ. (b,c) Reproduced with permission . Copyright 2011, IOP Publishing Ltd.…”

“…Tian and co‐workers recently introduced electrochemical deposition to the preparation of metallic wire for MCBJ operation . In the optimized MCBJ route, which was named as electrochemically assisted MCBJ (ECMCBJ), fabrication of adjustable nanogap only requires two economic and simple fabrication techniques: photolithography and electrochemical deposition, instead of the expensive and time consuming electron beam lithography.…”

Metal atomic contacts under defined environmental conditions

“…Recent developments in experimental techniques including scanning tunneling microscope (STM) break junctions and mechanically controllable break junctions (MCBJ) enable us to fabricate and investigate metal atomic contacts in various conditions, such as ultra high vacuum (UHV), ambient conditions including electrochemical environments [2][3][4][5][6][7][8]. Detailed investigations have been carried out in UHV at low temperatures (~4 K), because clean and stable metal atomic contacts can be fabricated under these conditions, and spectroscopic techniques including inelastic tunneling electron spectroscopy and point contact spectroscopy can be utilized at low temperatures [2][3][4][5].…”