NANOMETER-SCALE MECHANISM FOR THE CONSTRUCTIVE MODIFICATION OF CU SINGLE-CRYSTALS AND ALKANETHIOL PASSIVATED AU(111) WITH AN ATOMIC-FORCE MICROSCOPE

In-situ atomic force microscopy (AFM) is used to enhance Cu electrodep osition on Cu and Au single crystal electrodes. On Cu surfaces, the en hanced deposition effect depends primarily on tip-sample force, crysta llographic orientation, and solution pH. Enhanced Cu deposition is str onger on the (110) face of Cu than the (111) face which correlates wit h the reactivity of these lattices toward oxygen adlayer formation. Fo r a specific orientation, enhanced Cu deposition becomes less pronounc ed with decreasing solution pH. These results are consistent with a mo dification mechanism in which partially passivating oxygen adlayers me diate both normal and enhanced Cu deposition. The AFM tip-sample force physically creates defects in these adlayers, thus forming active sit es for Cu adsorption. The general applicability of this scheme is demo nstrated on Au(111) passivated with self-assembled octadecanethiol mon olayers.