Epitaxial Electrodeposition of Fe on Au(111): Structure, Nucleation, and Growth Mechanisms

Abstract

Iron epitaxial electrodeposition on Au(111) substrates is investigated using in situ scanning tunneling microscopy (STM) and ex situ X-ray diffraction (XRD). STM observations show that Fe grows quasi layer-by-layer at sufficiently negative potentials. XRD results indicate that Fe layers thicker than 3 ML are bcc and present the epitaxial relationship Fe(110) [1–10]||Au(111) [11–2]. They also show that the Fe lattice is uniaxially in-plane strained along Fe[1–10] and that the strain is progressively relieved with increasing layer thickness. The growth of Fe on a Ni layer deposited on Au(111) leads to strain free Fe layers with the same epitaxial relationship. The specific shape of Fe of monatomic islands suggests that the first Fe monolayer deposited on Au(111) presents a centered rectangular lattice similar to that of bcc Fe(110) but is stretched along Fe[1–10] by more than 8%.