Metal-molecule contacts and charge transport across monomolecular layers: measurement and theory.
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 (I-V) characteristics using extended Huckel theory coupled with a Green's function approach. The experimentally observed I-V characteristics are in excellent qualitative agreement with the theory.
Center for Bio/Molecular Science and Engineering, Naval Research Laboratory, Washington, District of Columbia 20375, USA. kushmerick@nrl.navy.mil
J G
JG
Kushmerick
D B
DB
Holt
J C
JC
Yang
J
J
Naciri
M H
MH
Moore
R
R
Shashidhar