Abstract
Charge transport studies across molecular length scales under symmetric and asymmetric metal-molecule contact conditions using a simple crossed-wire tunnel junction technique are presented. It is demonstrated that oligo(phenylene ethynylene), a conjugated organic molecule, acts like a molecular wire under symmetric contact conditions, but exhibits characteristics of a molecular diode when the connections are asymmetric. To understand this behavior, we have calculated current-voltage () characteristics using extended Huckel theory coupled with a Green’s function approach. The experimentally observed characteristics are in excellent qualitative agreement with the theory.
- Received 5 March 2002
DOI:https://doi.org/10.1103/PhysRevLett.89.086802
©2002 American Physical Society