Sol–gel synthesis of PZT thin films on FTO glass substrates for electro-optic devices

The optoferroelectric materials have attracted a great deal of attention in recent years. Lead zirconate titanate (PZT) thin films are fabricated on FTO glass substrates by sol–gel technique to investigate optical properties of the films. Heat treatment conditions and sol parameters are investigated to determine the optimum condition for fabricating the PZT thin films. Crack free almost pure perovskite crystal structure is formed at calcination temperature of 600 °C, for 5 min, and sol concentration of 0.33 mol/l. Increasing thickness of thin films raises the grain size and average roughness from 30 to 105 nm and 2.36 to 5.48 nm, respectively. FTIR analysis shows that 600 °C is an appropriate temperature for crystallization of PZT thin films due to the existence of metallic bond (M–O–M) in the spectrum. The films are characterized at different thicknesses for optical transmission and electrical investigation. Value of bandgap energy is estimated to be about 3.5 eV. It has been shown that the presence of rosette-type perovskite structure in the pyrochlore background has negative effect on capacitance and resistance of PZT films.