Formation of Platinum films by Electrochemical Atomic Layer Deposition (ALD) via Redox Replacement of UPD: Studies of Pb UPD as a Sacrificial Metal

摘要

The development of Surface limited Redox Replacement (SLRR) for formation of Platinum nanofilms using Pb UPD is described in this paper. The SLRR involved formation of Pb UPD and its spontaneous replacement by Pt, at the open circuit potential (OCP), from a Pt cation solution. This reaction was repeated to form thicker Pt nanofilms. An electrochemical flow cell system was employed for growing the Pt nanofilms. Changes in the OCP were monitored during the exchange process, and showed that exchange of Pt for Pb was complete in less than 3 minutes. The increase in Pb deposition charge from cycle to cycle, as well as AFM images, showed the deposition was not just layer by layer, 2D, but resulted in significant roughening. An attempt at electrochemical annealing by using adsorbed I atoms was also tried, but with no positive result. Films were analyzed by EPMA, and showed nearly uniform composition across the deposit, with no significant amount of Pb present.