Molecular wires in future nanoelectronics systems

Abstract

Physical performance limits of microelectronics devices demand a new form of electronics, in which molecules replace semiconductor-based structures. One of these limits is put up by destructive mass transport due to electromigration in nanoscale metallic wires, and the enormous heat generation caused by the extremely high charge density involved in signal transport. We propose a new approach, by which alloying elements in matrix metals are selected on the basis of their chemical valence, in order to improve these properties. Most probably will silicon-based chip technology and molecular electronics be developed in parallel during the next decade. The understanding of electrical conductivity along chemically designed molecular wires is required to that end. An outstanding feature of molecular charge transfer (CT) materials consists of the possibility to influence their properties by means of the coupled structural and electronic change of the molecular state. In the present work, the effect of ligand size on the degree of CT in Zn-Naphtholimines with TCNQ CT-complexes is studied. Incorporating either of H, CH 3, and CH 2CH 3 as aliphatic radical, we found, that a smaller ligand size brings about a stronger degree of CT. Vibration spectroscopy is applied in order to determine transition band frequencies and related shifts with ligand incorporation. The CT is determined from the band-shift of the C≡N stretch mode.