FORMATION AND PHOTO- ELECTROCHEMICAL CHARACTERIZATION OF ANODIC FILMS ON DIFFERENT VALVE- METAL ALLOYS

摘要

Anodic films on valve metals are of interest for investigating mechanisms of oxide growth as well as for possible application in electronic components, for instance as metal-oxide semiconductor junctions. Concerning the latter, the possibility of controlled modification of the solid state properties, such as band gap, flat band potential and dielectric constant, by use of "mixed oxides", is appealing from practical and theoretical viewpoints. Of relevance, it has been proposed recently that the band gaps of crystalline binary oxides correlate with the electronegativities of the constituents, thus suggesting the possibility of prediction of band gaps in ternary oxides, using an average electronegativity parameter for the cationic group and hence, tailoring of oxide properties. Further, the correlation can be extended to amorphous oxides, taking into account the effect of the amorphous structure on the band gap of the corresponding crystalline oxide.