The charge on the liquid interface surface is balanced with the charge in the diffuse layer and the charge in the semiconductor channel. The GCS model describes the electrical double layer (EDL) formed on the oxide surface consisting of an oxide-electrolyte interface, stern layer and the diffuse layer. The stern layer represents the effective uncharged (dielectric) region between the surface charge and counter-ions. The averaged permittivity of the stern layer varies with the charge density in its vicinity, ionic content of the electrolyte and several other factors but for simplicity of the analytical model, the stern capacitance (Cstern = 0.8F/m 2 ) is kept constant as used in Van Hal, 1996 . However, even with variable Cstern that may lead to the change in potential amplitude due to series connection with diffuse layer capacitance, the fingerprints that we have discovered will still be present with slightly different values that can be observed by the phenomenological correction compensated by the effective proton affinities. The surface potential within the GCS model is the summation of the potential drop across the stern layer (Vstern) and the potential at the shear plane (zeta potential, < = ):