AVS 49th International Symposium
    Organic Films and Devices Wednesday Sessions
       Session OF+EL+SS+SC-WeM

Paper OF+EL+SS+SC-WeM5
Controlling Metallic Contacts to Molecular Electronic Devices

Wednesday, November 6, 2002, 9:40 am, Room C-102

Session: Metal-Organic Interfaces
Presenter: A.V. Walker, Pennsylvania State University
Authors: A.V. Walker, Pennsylvania State University
T.B. Tighe, Pennsylvania State University
O. Cabarcos, Pennsylvania State University
B.C. Haynie, Pennsylvania State University
D.L. Allara, Pennsylvania State University
N. Winograd, Pennsylvania State University
Correspondent: Click to Email
In the development and design of molecular electronic devices, it is vital to understand the nature of the metal-organic monolayer interaction. To fully characterize these interactions, we employ a multi-technique approach using time-of-flight secondary ion mass spectrometry (ToF SIMS), infrared spectroscopy (IRS), x-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations. Using an unfunctionalized molecular wire (4-[4?-(phenylethynyl)-phenylethynyl]-benzenethiol) monolayer on Au, we demonstrate that the metal-monolayer contact can be varied from complete destruction of the monolayer to contact formation at the monolayer terminus to complete penetration through the layer. For example, we show that upon deposition of Cu or Ag, the Cu and Ag atoms simultaneously interact with the terminal phenyl ring and penetrate to the Au/S interface. In contrast, Au penetrates through the monolayer at all coverages studied. By using metals specifically tailored for the chemistry of the device molecule as well as for electronic states, the characteristics of the metal-molecule contact can also be controlled. These types of data provide a foundation for rational design of contacts in molecular electronic devices.