OPTICAL-PROPERTIES OF PZT AND PMZT SPUTTERED THIN-FILMS

Optical properties of manganese doped lead zirconate titanate, PMZT (0/60/40), (0/20/80) and (4/60/40) thin films deposited by r.f. magnetron sputtering have been investigated in terms of optical transmission measurements. The absorption coefficient and the refraction index of samples before and after annealing have measured as a function of wavelength from 350 to 2000 nm. The optical methods used for the calculation of the key optical constants axe discussed. They allow to establish a relation between inhomogeneities in the films and deviations of the refraction index in the visible range. The measured transmission spectra have been compared with a simulated one. Based on the analysis of dispersion in refractive indices the refractive-index dispersion parameters in the single-term Sellmeier relation were determined to be 8.60-10.3.10(-14) eVm2. Calculated values of absorption coefficient indicate, that the optical absorption edge for as-deposited PZT and PMZT is in the range 2.1-2.2 eV. For the annealed samples, however, it is not reached at 3.5 eV.