ELECTRICAL AND PHYSICAL CHARACTERIZATION OF BILAYER CARBOXYLIC ACID FUNCTIONALIZED MOLECULAR LAYERS
Sujitra J. Pookpanratana, Joseph W. Robertson, Cherno Jaye, Daniel A. Fischer, Curt A. Richter, Christina A. Hacker
We have used Flip Chip Lamination (FCL) to form monolayer and bilayer molecular junctions of carboxylic acid-containing molecules with Cu atom incorporation. Carboxylic acid-terminated monolayers are self-assembled onto ultrasmooth Au using thiol chemistry and grafted onto n-type Si. Prior to junction formation, monolayers are physically characterized using polarized infrared absorption spectroscopy, X-ray photoelectron spectroscopy, and near edge X-ray absorption fine structure spectroscopy, confirming molecular quality and functional group termination. FCL was used to form monolayer junctions of carboxylic acid-terminated Au to H-terminated Si, or bilayer junctions of carboxylic acid monolayers on Au and Si. After junction formation, these monolayer and bilayer junctions were characterized by p-polarized backside infrared spectroscopy to verify their molecular structural integrity. The electrical measurements of these junctions were performed, and we find that the current through the junction is attenuated as the effective molecular length within the junction increased.