AVS 52nd International Symposium
    Electronic Materials and Processing Thursday Sessions
       Session EM1-ThM

Paper EM1-ThM8
Tunneling Transport through Benzoate on Cu(110)*

Thursday, November 3, 2005, 10:40 am, Room 309

Session: Molecular Electronics
Presenter: D.B. Dougherty, University of Pittsburgh
Authors: D.B. Dougherty, University of Pittsburgh
P. Maksymovych, University of Pittsburgh
J.T. Yates Jr., University of Pittsburgh
Correspondent: Click to Email
The possible use of single molecules as devices in electronic circuits requires a fundamental understanding of the influence of the details of the linkage and charge transport to a macroscopic contact. Molecular orientation, chemical bond strength and location, and energetic location of molecular orbitals may all play a role in determining the possible use of a given molecule/contact system. Thus, detailed experimental studies of simple molecules in well-defined and reproducible configurations are necessary to supplement and guide more technologically relevant work. Significant progress has been made in understanding the transport properties through long chain molecules linked to Au surfaces by a thiolate group.@footnote 1@ These linkages are not the only potentially interesting candidates for electronics. In fact, the enormous chemical variety available is one of the great advantages of using organic molecules in devices. We have studied the electronic transport properties of benzoate molecules on a clean Cu surface which are linked by a carboxylate group instead of a thiolate.@footnote 2@ Such a linkage can be strong and surface-site specific and may therefore result in useful and reproducible electrical contact. More importantly, it provides a tool for addressing fundamental issues in single molecule transport. Using scanning tunneling spectroscopy, we have measured the I/V and conductance characteristics of differently oriented benzoate molecules chemisorbed on a Cu(110) surface. Benzoate molecules adsorbed with their plane perpendicular to the surface have a diminished conductivity in the low bias regime when compared to molecules with their plane parallel to the surface. The conductivity is found to be independent of temperature. *Supported by the W.M. Keck Foundation and a Japanese NEDO grant. @FootnoteText@ @footnote 1@ W. Wang et al., Rep. Prog. Phys. 68 (2005) 523.@footnote 2@ B.G. Frederick et al., Surf. Rev. Lett. 3 (1996) 1523.