Epitaxial growth of Ag on Au(111) by monolayer restricted galvanic displacement

Abstract

The development of a new method for epitaxial growth of metals in solution by galvanic displacement of layers pre-deposited by underpotential deposition (UPD) is discussed and experimentally illustrated. Cyclic Voltammetry and Scanning Tunneling Microscopy are employed to carry out and monitor a "quasi-perfect", two-dimensional growth of up to 35 monolayers (MLs) of Ag on Au(111) by repetitive galvanic displacement of underpotentially deposited Tl and Pb monolayers. A comparative study emphasizes the displacement stoichiometry as an efficient tool for thickness control during the deposition process and as a key parameter that affects the deposit morphology, The excellent quality of layers deposited by monolayer-restricted galvanic displacement is manifested by a steady UPD voltammetry and ascertained by a flat and uniform surface morphology maintained during the entire growth process. An X-ray Photoelectron Spectroscopy analysis finds no traces of Pb in the Ag deposit. copyright The Electrochemical Society.