Infrared optical properties of PbZr_xTi_1-xO₃thin films

Lead zirconate titanate PbZr_xTi_1-xO₃ (PZT) thin films grown on Pt/Ti/SiO₂/Si substrates with x equals 0.3 and 0.5 have been measured by infrared spectroscopic ellipsometry (IRSE). The IRSE data measured at an angle of incidence 75 degree(s) for x equals 0.3 and 70 degree(s) for x equals 0.5 are fitted by a proposed dielectric function formula. The refractive index and extinction coefficient of PZT with x equals 0.3 and 0.5 are determined in the spectral range of 2.5-12.5 micrometers. As the wavelength increases, the refractive index decreases, on the contrary, the extinction coefficient increases. The absorption coefficient for x equals 0.5 is greater about 1.5 times than that for x equals 0.3. The effective static charges of PZT is also derived by fitting the IRSE data. The values obtained are 1.792 +/-0.031 and 1.838 +/-0.0465 for PZT with x equals 0.3 and 0.5, respectively. The results reveal that charge transfer is not complete in PbZr_xTi_1-xO₃ thin films.