Electronic and structural characterization of underpotentially deposited submonolayers and monolayer of copper on gold (111) studied byin situx-ray-absorption spectroscopy

Abstract

We report on the first in situ study of the electronic state and the structure of underpotentially deposited submonolayers of Cu on Au(lll) by x-ray-absorption spectroscopy. We found (i) various ordered adlayer structures, dependent on coverage, time, and direction of the potential scan, and (ii) strong interactions of Cu and oxygen and charge transfer from Cu to Au. During the deposition, the initial (VJxVJ) structure at 0.3 monolayer evolved to an equilibrium with the c(5x5). The latter and the (lxl) phases were observed at 0.6 and 1 monolayer, respectively. The three structures are present at 0.6 monolayer during the stripping scan.

Structural Study of Electrochemically Deposited Cu on p-GaAs(100) in H2SO4 Solution by In Situ Surface-Sensitive X-ray Absorption Fine Structure Measurements

“…64 The results of parameter fitting showed that O atoms, which should be in a water molecule and/or sulfate anion, coordinate to the nanoclusters. Tadjeddine et al reported that the Cu-O distances for 1 ML Cu on Au(100) and 0.3 ML Cu on Au-(111) 18 in sulfate solution are 1.99 and 1.95 Å, respectively. 17 Abruña et al also reported that the Cu-O distance for 0.5 ML of Cu on Pt(111) in 0.1 M H 2 SO 4 solution is 1.99 Å.…”

“…[9][10][11] To fully understand the deposition process, it is essential to elucidate the local structure of the substrate and the deposited overlayer on an atomic scale. [12][13][14][15][16] Although the structures of electrochemically deposited Cu on metal have already been investigated by many research groups, [17][18][19][20][21][22] only a few studies on the electrochemical deposition of Cu on semiconductor electrodes have been carried out. [23][24][25][26][27][28][29] GaAs is one of the most attractive semiconductor materials used in various electronic devices and dry/wet solar cells.…”

Underpotential deposition of Cu on Au(111) in sulfate-containing electrolytes: A theoretical and experimental study

“…The UPD of Cu on Au(111) in sulfate-containing electrolytes has been extensively studied, both by in situ techniques like CV [7,8,10,11,[45][46][47][48][49][50][51], chronocoulometry [45][46][47][48][49][50][51], scanning tunneling microscopy (STM) [9,45,52,53], atomic-force microscopy (AFM) [54], Fourier-transform infrared spectroscopy (FTIR) [55], X-ray-absorption spectroscopy (EX-AFS and XANES) [56][57][58], surface X-ray scattering [59,60], quartz crystal microbalance (QCM) [47,59], and by ex situ techniques, such as LEED, RHEED (reflection high-energy electron diffraction) and AES [10,11,[61][62][63]. Electrolyte compositions used in several CV experiments (including the present work) are listed in Table I, together with potential scan rates and observed current-peak separations.…”

New Insights into Evaluation of Kinetic Parameters for Potentiostatic Metal Deposition with Underpotential and Overpotential Deposition Processes

“…Many aspects of both UPD and OPD processes have been described in great detail, including electrodeposition onto the Au(111) surface, the structure of the copper-UPD adlayer and its mechanism of formation, and the influence of different (coadsorbed) anions on UPD adlayer formation. 1,2 Recent progress in the field has made use of modern, in situ techniques for structural characterization such as STM, [3][4][5][6][7][8][9][10][11][12][13] in situ X-ray measurements, [14][15][16][17][18][19] in situ electrochemical quartz crystal microbalance studies, 20,21 and updated electrochemical studies. [22][23][24][25] Studies of copper OPD onto Au(111) have focused on determining deposit morphology, characterizing kinetics of the electronucleation process, and examining how different molecular additives influence the course of the deposition process.…”