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 obtained. The spectral structure was analysed with emphasis on the evolution of the electronic structure from an insulating to a conducting polymer. The threshold energy and the broadening parameter as well as the dimension are determined by the fractional derivative spectrum technique which was previously proposed by X.-F. He and D. Mo (Chin. Phys. Lett., 3 (1986) 565).