Single-molecule devices: materials,structures and characteristics

This review article provides a brief survey of materials, structures and current state-of-the-art techniques used to measure the charge conduction characteristics of single molecules. Single molecules have been found to exhibit several unique functionalities including rectification, negative differential resistance and electrical bistable switching, all of which are necessary building blocks for the development and configuration of molecular devices into circuits. Conjugated organic molecules have received considerable interest for their low fabrication cost, three dimensional stacking and mechanical flexibility. Furthermore, the ability of molecules to self-assemble into well-defined structures is imperative for the fabrication of molecule based circuits. The theoretical formalisms are presented for studying single-molecule Coulomb blockade effects, ballistic transport in a molecular chain and electromagnetic coupling between a surface-plasmon field and a single molecule. Moreover, the experimental current–voltage results are discussed using basic principles of carrier transport mechanisms.