Controlling the structural and electrical properties of metal/monolayer/metal devices

Abstract

Molecular electronics, in which a single molecule or a single layer of molecules that can perform some electronic function when sandwiched between two electrodes, has potential to serve a role in the development of a new technology that could overcome the difficulties now being encountered during top-down scaling of conventional silicon technology. The study of single-molecule junctions has contributed enormously to understand charge and heat transport phenomena at the molecular scale. However, in looking towards an electronics technology, metal|monolayer|metal systems offer an advantage over single-molecule junctions since two dimensional (2D) monomolecular structures up to 1015 molecules·cm-2 can be fabricated, leading to advantages in statistical variation of individual mono-molecular junctions, amplification of current response and ease of fabrication. In looking to extent from single molecule to monolayer junctions, it is critical to understand the effect of intermolecular interactions, e.g., van der Waals interactions and polarization effects on electronic transport properties. Our group is working in several challenges which have to be overcome before the molecular junctions suitable for developing the science of molecular electronics can be translated to true device structures and considered as a viable technology capable of reaching the market. These include the use of assembly strategies to fabricate well-ordered monomolecular films on top of a conducting electrode, study of different contacting groups to form robust and stable metal-molecule junctions, and development of new methods for the fabrication of the top-contact electrode. The electrical properties of these nascent metal/molecule/metal devices are characterized by either the STM touch-to-contact method or a c-AFM using the Peak Force Tuna mode (PF-TUNA™). In this presentation, a summary of the most relevant results of our research in these topics are presented together with future actions.