“…According to the Wagner polarization analysis, 16 the total electronic current, I, is given by eqn. (3), where I e and I h are the currents due to electrons and holes, respectively, R is the gas constant, T is the absolute temperature, A is the electrode area, L is the sample thickness, F is the Faraday constant, E is the applied voltage, and s e and s h are the conductivities due to electrons and holes, respectively.…”