METAL OVERLAYERS ON ORGANIC FUNCTIONAL-GROUPS OF SELF-ORGANIZED MOLECULAR ASSEMBLIES .1. X-RAY PHOTOELECTRON-SPECTROSCOPY OF INTERACTIONS OF CU/COOH ON 11-MERCAPTOUNDECANOIC ACID

X-ray photoelectron spectroscopy spectra were recorded after sequential deposition of submonolayer amounts of copper on an organized molecular assembly (OMA) of HS(CH2)10COOH 11-mercaptoundecanoic acid (MUA) on 80-nm-thick gold films on silicon substrates. The self-assembly process results in stable monolayers with the thiol group attached to the gold film and the COOH group as the outer monolayer. Copper deposited in vacuum interacts with the surface of the MUA OMA to produce a unidentate copper complex with the single bonded oxygen atom of the acid monolayer. The data do not support forming a bidentate copper complex or chemical interaction of the double bonded oxygen atom of the acid group with copper. The maximum charge residing on the copper atom of the complex is + 1 with one charged copper atom on the surface per MUA molecule of the OMA.