Study of the interaction at rest potential between silicotungstic heteropolyanion solution and GaAs surface

In this paper, we demonstrate the possibility of obtaining a modification of GaAs toward the hydrogen evolution reaction (HER) at the rest potential in an acidic solution of the (SiW12O40)4− heteropolyanion (HPA). This phenomenon is the consequence of a chemical modification of the GaAs surface. The X-ray photoelectron spectroscopy (XPS) results and profile measurements clearly demonstrate that GaAs is oxidised by this Keggin HPA. The constant etching rate is 10 nm h−1. At the same time, on the GaAs surface, a deposit is formed that is composed presumably of As0 and WO3. Thus, the Keggin structure (SiW12O40)4−, usually stable, is not preserved on the surface of GaAs.