Nanopores-based junctions

A sharp peak at —2 V, demonstrating a dear NDR effect, was observed in the /(V) characteristics of a nanopore junction containing substituted OPE molecule 84d when measured at 60 K [44]. Later studies, involving nitro- and amino-substituted OPE-based nanopores, also demonstrated a controllable memory effect of the junction [71b]. This effect was based on the switching between a high and a low conductivity state of the OPE, which could be controlled by the bias voltage. 

An early nanopore study focused on an asymmetric Au-molecule-Ti junction based on thiol end-capped biphenyl 81b molecules [45], The asymmetry of the structure led to the observation of a prominent rectifying behavior with larger current when the Ti electrode was negatively biased. Recent work by Bao and coworkers [72] has shown that vapor deposition of Ti on SAMs results in penetration of the monolayer, thus destroying it. Similar observations were made using Au and A1 deposition. However, destruction of the monolayer could in this case be prevented if SAMs of dithiols were used, since the Au or A1 would react with the free thiol end. 

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-... 

The selection made covers the first efficient and stable system based on the ternary chalcopyrite CulnSe2, an electrochemical treatment to avoid a toxic etching step in solid-state CIS device fabrication, the first stable and efficient liquid-junction solar cell (InP), and a novel concept where nanoemitters, interspersed in a nanoporous passivating film, are used to scavenge excess minority carriers. 

---