Abstract
In the present work sputtered magnetite (Fe3O4) and oxidised magnetite layers which exhibit different Fe(II) contents were investigated with impedance spectroscopy and photoelectrochemistry and compared with the passive film on iron in berate buffer (pH 8.4). Evaluating the impedance data according to the Mott-Schottky theory it was possible to show that the capacitance is linked with the doping concentration rather than the film thickness. The comparison of these data to the doping concentration of the passive film on iron formed at different potentials resulted in evidence that the doping species is Fe(II). Photo electrochemical investigation of the passive film and the sputtered oxide layers showed that a decrease in doping concentration from 4.10(27) m(-3) to 4.10(26) m(-3) yields an increase in photocurrent intensity. Further an increase of photocurrent with increasing passive film thickness was found using a light reflectance measuring technique.