Formation of arsenic sulfide on GaAs surface under illumination in acidified thiourea electrolytes

► This research is about corrosion inhibition of GaAs semiconductor electrodes by using thiourea acidified electrolytes. ► Thiourea was oxidized on GaAs surface and a corrosion inhibition film of As-sulfide was formed. ► The surface composition of the inhibition film was characterized by XPS. ► Surface morphology was investigated by SEM. ► Electrochemical techniques including impedance measurements were used to investigate GaAs and As-sulfide/GaAs corrosion.