AN ELLIPSOMETRIC AND EIS STUDY OF MANGANESE OXIDE FILMS

M.HERNANDEZ UBEDA; L.M.GASSA; B.A. LÓPEZ DE MISHIMA; M.LOPEZ TEIJELO

Porto

Congreso; 45th Annual Meeting International Society Electrochemistry; 1994

International Society Electrochemistry

The deposition of manganese oxide films as well as charge-discharge cycles were studied by in-situ ellipsometry. EIS measurements of oxidized and electro reduced oxide were also performed. Ellipsometric measurements indicate that optical properties of manganese oxide are sensitive to the deposition condition. The optical parameters obtained during the oxide growth can be adequately fitted by means of a single layer model for an absorbent films on the metal substrate up to a thickness of ca 100 nm. Electroreduction in the alkaline borate solutions leads to a decrease in both the refractive index and lf. The electroreduced oxide films is almost transparent ( kf =0). The EIS results are explained in the basis of the modifies Randles circuit by the addition of the limiting capacitance which takes into account the so-called ?finite length effects?.