Novel one-dimensional nanogap created with standard optical lithography and evaporation procedures

Abstract

This article details a simple four-step procedure to create a one-dimensional nanogap on a buried oxide substrate that relies on conventional photolithography performed on a stack of silicon/silicon oxide/silicon, metal evaporation, and hydrofluoric acid oxide removal. Once the nanogap was fabricated it was bridged with an assembly of 1,8-octanedithiol and 5 nm Au nanoparticles capped with a sacrificial dodecylamine coating. Before assembly, characterization of the nanogaps was performed through electrical measurements and SEM imaging. Post assembly, the resistance of the nanogaps was evaluated. The current increased from 70 fA to 200 microA at +1 V bias, clearly indicating a modification due to nanoparticle molecule assembly. Control experiments without nanoparticles or octanedithiol did not show an increase in current.

Nanogap Electrodes

“…This prominent study demonstrates the possibility of fabricating nanostructures with a single or few molecules connected to two nanoelectrodes by bottom-up chemical assembly. Alternatively, inorganic films [112][113][114][115] with a precise atomic thickness separating two metal leads can also serve as templates, and are referred to as atomic rulers. The inorganic spacing layer should also be selectively removed in some way like the organic molecular rulers, at the same time leaving the metal leads unaffected.…”

Advantages of Prefabricated Tunnel Junction-Based Molecular Spintronics Devices

“…3,102 A TJMD approach also democratizes opportunities for worldwide researchers. A TJMD's tunnel junction have been produced using photolithography and physical vapor deposition systems 23 ; after that molecular self-assembly process commenced to establish molecular conduction channels as the¯nal step to complete molecular device fabrication.…”

Nano-electromechanical zero-dimensional freestanding nanogap actuator

“…Previous attempts to form nanogaps have been made by moving two tips mounted on macroscopic actuators close together, which prevents high-bandwidth gap control. Various methods of conductive nanogap nanofabrication have been developed: mostly direct electron-beam lithography, 7 mechanical pulling, 8 shadow masking, 9 electromigration, 10 electroplating, 11 focused ion beam (FIB), 12 angled metal evaporation, 13 and silicon micromachining. 3,14,15 Most nanogaps are fabricated by laborious serial processes that would introduce a large variation in gap sizes or on a substrate that would interfere with electrical and optical measurements.…”