ELLIPSOMETRIC SPECTRA AND FRACTIONAL DERIVATIVE SPECTRUM ANALYSIS OF POLYANILINE FILMS

Ellipsometric spectra of polyaniline films were measured for the first time. The complex dielectric function and the refractive index in the UV-visible range of both insulating and conducting polyaniline were o btained. The spectral structure was analysed with emphasis on the evol ution of the electronic structure from an insulating to a conducting p olymer. The threshold energy and the broadening parameter as well as t he dimension are determined by the fractional derivative spectrum tech nique which was previously proposed by X.-F. He and D. Mo (Chin. Phys. Lett., 3 (1986) 565).