GaAs/electrolyte junctions are characterized by steady state photocapacitance measurements without (single beam experiment) or with added interband illumination (dual beam experiment). This original approach allows to give unambiguously the surface state distribution and to follow its evolution during electrochemical processes: results show the presence of two corrosion related states at E C −0.98 eV and E C −1.14 eV which behave differently under corrosion or photocorrosion conditions. It is shown that surfaces modified by electro‐deposition of discontinuous metal films exhibit metal‐induced surface states responsible for charge transfers.