Compensating the Effects of Frequency Dispersion in Mott–Schottky Analyses of Passive Films

Semiconductor electrochemical study of the passivity limits of austenitic stainless-steel in H2S-containing brines

“…The experiments for the Mott–Schottky testing were performed by polarising sequentially at 50 mV intervals from the recorded OCP up to the observed pitting potential of the steel tested (vs SCE), with an amplitude of ± 10 mV at a constant frequency of 1 kHz. The value of the frequency used in the measurements was selected with the aim of minimising any faradaic effects that would affect the capacitance value, as it is observed from a previous study by the authors and reported in the literature [29,30]. The Mott–Schottky test was performed at least three times at each testing condition contemplated in the experimental matrix to obtain information about the reproducibility of the behaviour observed.…”

The Impedance Response of a Passive Film Revisited by a Double Modulation Technique

“…According to this approach, the capacity variation as a function of the electrode potential is interpreted using the classical concepts of semiconductor‐electrolyte interface, thus in terms of flat‐band potential and charge carrier density ,. However, the examination of the abundant literature on the subject shows a quasi‐systematic dependence of Mott‐Schottky's capacitance on the frequency of measurement …”

“…[21,22] However, the examination of the abundant literature on the subject shows a quasisystematic dependence of Mott-Schottky's capacitance on the frequency of measurement. [23][24][25] Numerous interpretations have been proposed according to the nature of the film, often evoking the non-ideality of the semi-conductive properties of the passive film such as surface states, [26] the non-stationarity of the oxide film, [27] but the use of single frequency capacitance measurement strongly restricts the possibility of data interpretation.…”