Contacting single molecules to metallic electrodes by scanning tunnelling microscope manipulation: model systems for molecular electronics

• Published in: Journal of physics. Condensed matter 2006-08, Vol.18 (33), p.S1887-S1908
• Main Authors: Grill, L, Moresco, F
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: structure, mechanical and thermal properties; Electron, ion, and scanning probe microscopy; Electronics; Exact sciences and technology; Molecular electronics, nanoelectronics; Physics; Scanning probe microscopy: scanning tunneling, atomic force, scanning optical, magnetic force, etc; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; Structure of solids and liquids; crystallography
• ISSN: 0953-8984; 1361-648X
• DOI: 10.1088/0953-8984/18/33/S08

The electronic contact between a molecular wire and a metallic electrode will play an important role in future molecular electronics as its properties determine the conductivity of the molecule-metal system. Scanning tunnelling microscopy manipulation reveals various advantages for the investigation of electronic contacts at the atomic scale. In this review, several examples of molecular wire-electrode systems are presented, where single molecules are placed in contact in a controlled way. Changed chemical structures of the molecule and, on the other hand, different shapes and dimensions of electrodes lead to a variety of contact configurations. The contact can be characterized using the additional contribution to the tunnelling current, but also using the influence on the electronic states of the electrode and the molecule. The quality of the contact is discussed in terms of the vertical distance between the molecular wire and the metal atoms and of the chemical composition of the molecular end group.