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Photoelectrochemical Processes at n-GaAs(100)/Aqueous HCl Electrolyte Interface: A Synchrotron Photoemission Spectroscopy Study of Emersed Electrodes

Lebedev, Mikhail V. and Calvet, Wolfram and Mayer, Thomas and Jaegermann, Wolfram (2014):
Photoelectrochemical Processes at n-GaAs(100)/Aqueous HCl Electrolyte Interface: A Synchrotron Photoemission Spectroscopy Study of Emersed Electrodes.
In: The Journal of Physical Chemistry C, 118 (24), ACS Publications, pp. 12774-12781, ISSN 1932-7447,
[Online-Edition: http://dx.doi.org/10.1021/jp500564c],
[Article]

Abstract

High-resolution synchrotron photoemission spectroscopy has been applied to detail the electrochemical and photoelectrochemical corrosion reactions at the liquid junction n‑GaAs(100)/1 M aqueous HCl solution. Under anodic polarization of 1.8 eV, the main process initiated by the presence of holes in the Ga−As bonding states of the valence band is the formation of soluble gallium chloride complexes and insoluble elemental arsenic on the surface. In addition, arsenic hydroxide forms, which reacts further to soluble HAsO2. In toto, the As/Ga atomic ratio increases, which is accompanied by an increase of the work function. The anodic decomposition reaction is enhanced by illumination as more holes reach the n-semiconductor/electrolyte junction. Under cathodic polarization of 1.5 eV, only minor changes are observed in Ga and As core-level spectra, giving no indication of corrosion, but specific adsorption of hydrated HCl molecules and/or Cl −ions considerably modifies valence bandspectra.

Item Type: Article
Erschienen: 2014
Creators: Lebedev, Mikhail V. and Calvet, Wolfram and Mayer, Thomas and Jaegermann, Wolfram
Title: Photoelectrochemical Processes at n-GaAs(100)/Aqueous HCl Electrolyte Interface: A Synchrotron Photoemission Spectroscopy Study of Emersed Electrodes
Language: English
Abstract:

High-resolution synchrotron photoemission spectroscopy has been applied to detail the electrochemical and photoelectrochemical corrosion reactions at the liquid junction n‑GaAs(100)/1 M aqueous HCl solution. Under anodic polarization of 1.8 eV, the main process initiated by the presence of holes in the Ga−As bonding states of the valence band is the formation of soluble gallium chloride complexes and insoluble elemental arsenic on the surface. In addition, arsenic hydroxide forms, which reacts further to soluble HAsO2. In toto, the As/Ga atomic ratio increases, which is accompanied by an increase of the work function. The anodic decomposition reaction is enhanced by illumination as more holes reach the n-semiconductor/electrolyte junction. Under cathodic polarization of 1.5 eV, only minor changes are observed in Ga and As core-level spectra, giving no indication of corrosion, but specific adsorption of hydrated HCl molecules and/or Cl −ions considerably modifies valence bandspectra.

Journal or Publication Title: The Journal of Physical Chemistry C
Volume: 118
Number: 24
Publisher: ACS Publications
Divisions: 11 Department of Materials and Earth Sciences > Material Science > Surface Science
11 Department of Materials and Earth Sciences > Material Science
11 Department of Materials and Earth Sciences
Date Deposited: 26 Feb 2015 10:15
Official URL: http://dx.doi.org/10.1021/jp500564c
Identification Number: doi:10.1021/jp500564c
Funders: This work was supported in part by Russian Foundation for Basic Research (Project 13-02-00540).
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