Electromigrated break junctions

A break junction can also be created by passing a current (0.5-1.0 V) through an Au nanowire (<20 nm diameter) defined by electron-beam lithography and shadow evaporation. Such electromigrated break junctions (EMBJs) have yielded reproducible 1-3 nm gaps between electrodes [48-50]. 

A break junction is formed by breaking a thin metallic wire to produce a narrow gap between two conductors. Bridging this gap by a single or a few molecules creates a metal-molecule-metal junction, as illustrated in Fig. 10.8. The metallic wire can be broken by mechanical deformation (mechanically controlled break junctions, MCBs) or by electromigration. 

The abihty to measure and to control charge transport across nanometer-scale metal-molecule-metal junctions represents a key step toward the realization of molecular-based electronics [190-192]. Various experimental approaches have been employed to study molecular junctions in two- and three-terminal configurations. These include scanning probe microscopies (STM, STS, CP-AFM) [193-208], crossed-wire junctions [209], mechanical [210-215] and electromigration [216,217] break junctions, nanopores [218] and mercury drop electrodes [219]. Approaches in condensed media, and in par-... 

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