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Epitaxial Growth of Gold on HSi(111): The Determining Role of Hydrogen Evolution
Author(s) -
Prodhomme Patricia,
Warren Samantha,
Cortès Robert,
Jurca Hugo Feitosa,
Maroun Fouad,
Allongue Philippe
Publication year - 2010
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201000236
Subject(s) - nucleation , epitaxy , monolayer , hydrogen , crystallography , morphology (biology) , chemistry , chemical physics , diffraction , semiconductor , materials science , nanotechnology , layer (electronics) , optoelectronics , physics , organic chemistry , biology , optics , genetics
Abstract The potential dependence of gold electrodeposition on H‐terminated Si(111) is studied in acidic electrolyte by means of atomic force microscopy and X‐ray diffraction. The Au films (≤66 monolayers (ML)≈16 nm) are found to be (111)‐oriented and in strong epitaxy with the Si(111) surface lattice, with two in‐plane orientations separated by 180°. The deposit morphology is controlled by the deposition potential and can be islandlike or atomically flat. The flat morphology is accompanied by a preferential growth of 180°‐rotated Au planes with respect to the Si bulk lattice which takes place at potentials where the hydrogen evolution reaction occurs. Obtaining ultraflat Au layers on Si(111) contrasts with the commonly observed islandlike morphology of electrodeposited films on semiconductors. This behavior is discussed in terms of a nucleation coupled with hydrogen evolution reaction (HER) and an enhanced Au adatom mobility induced by this reaction.