Electrochemical Wiring of a Metal Nanofilament to Form a Molecular Junction

Leveraging the functionalities of molecules in electronic devices seems promising for the development of next-generation technologies. However, wiring an electrode to a molecular layer is challenging. Here, we introduce a method for connecting a microscale metal electrode to a molecular layer using an atomic switch that controls the formation and rupture of a metal nanofilament using a bias voltage. Specifically, a 1,4-benzenedithiol (BDT) molecular layer is embedded within an atomic switch. A bias sweep applied to the Ag top electrode induces a transition between a high-conductive state (2 mG₀, where G₀ = 2e²/h) and a low-conductive state (35 μG₀), with both states exhibiting nonvolatile operation. Current-voltage analysis and density functional theory simulation reveal that a Ag/BDT/Ag junction with approximately 20 molecules forms in the high-conductive state. Thus, our method is effective for the wiring of a microscale electrode to a nanoscale molecular layer.