Characterization of molecular electronic transport is an active part of the research field in nanotechnology. The main underlying idea is to use single molecules as active elements in nanodevices [1]. As a consequence, the proper fabrication of a molecule–electrode contact is a crucial issue [2],[3] and several applications can be envisioned. For example, the variation of the electrical conduction of metal–molecule–metal junctions can be used in biosensing for electrochemical detection of different crucial biomarkers. Possible applications include biomedical diagnostics and the monitoring of biological systems. In particular, the detection of single proteins might become the starting point for monitoring drugs, developing clean energy systems, fabricating bio-optoelectronic transistors, and developing other innovative devices and systems.

The fabrication of nanogaps

Nanogap electrodes (NGEs, defined as a pair of electrodes separated by a nanometer-sized gap) are fundamental tools for characterizing the electric properties of material at the nanometer scale, or even at the molecular scale. They are also important building blocks for the fabrication of nanometer-sized devices and circuits.

Molecular-based devices possess unique advantages for electronic applications with respect to conventional components [4], such as lower cost, lower power dissipation and higher efficiency. Specific molecules can be not only recognized, but also self-assembled on such NGEs, thus leading to elaborate geometries for the study of distinct optical and electronic properties.