Electrochemical Atomic Layer Deposition of Pd Ultrathin Films by Surface Limited Redox Replacement of Underpotentially Deposited H in a Single Cell

Abstract

This work illustrates the application of a surface limited redox replacement (SLRR) protocol for the electrochemical atomic layer deposition (E-ALD) of Pd ultrathin films on Au in a single cell using underpotentially deposited H (HUPD) as the sacrificial mediator. The facile deposition approach presented herein requires neither the use of sophisticated instrumentation nor the presence of metal ions other than the Pd(II) chloride complex. This provides for maximum growth efficiency and eliminates potential contamination of the deposit thereby rendering the Pd deposition a “greener” process. The growth progress is monitored by open circuit chronopotentiometry while the roughness evolution of accordingly deposited Pd films is assessed by cyclic voltammetry (CV) of HUPD and CuUPD. The CV results indicate the deposition of smooth Pd films occurring for up to 30 SLRR cycles (20 equiv monolayers) followed by a rapid transition to dendritic growth at higher thickness. The quasi-2D growth, resulting in smooth and ...