SXPS study of model GaAs(100)/electrolyte interface

Model GaAs(100)/electrolyte interfaces are prepared in vacuum by co-adsorption of Cl-2 and 2-propanol molecules at LN2 temperature. On adsorption of Cl-2 molecules gallium chlorides, elemental arsenic and arsenic chlorides are formed. Co-adsorption of 2-propanol causes formation of additional GaCl3 and AsCl, as well as soluble/volatile As-based complexes, which are released from the surface depleting the sur-face by arsenic. Comparison of the As 3d and Ga 3d spectra obtained after heating the model interface to room temperature with the corresponding spectra obtained after emersion of the GaAs(100) surface from HCl/2-propanol solution allows to conclude that in HCl solution Cl-ions attack gallium sites and H+ ions mostly attack arsenic sites. (C) 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim