engleski

Semiconducting properties of the oxide films formed on tin: Capacitive and XPS studies

Cyclic voltammetry, electrochemical impedance spectroscopy, X–ray photoelectron spectroscopy, and capacitive studies confirmed the presence of different types of film grown on tin during anodic polarization in a borate buffer solution, pH 8.4. The film composition and barrier properties showed the characteristic changes of the spectra at the formation potentials selected. Sn(IV) oxide species dominated in the film formed at 1.0 V, while the film formed at 0.5 V was correlated to a mixture of Sn(II) and Sn(IV) oxide species, exhibiting higher corrosion resistance in comparison to that of the first one. Semiconducting behavior of the passive films on tin were discussed in the framework of the classical energy–band model of semiconductors and the potential distribution at the film|solution interface. The electronic structure of the films was explored using Mott–Schottky analysis taking into account the frequency dispersion in order to obtain accurate values of the charge carrier density and the flat band potential. Both films were found to be n–type semiconductors.

tin ; oxide films ; electrochemical impedance spectroscopy ; X–ray photoelectron spectroscopy ; capacitance measurements

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