STRUCTURAL, ELECTRICAL AND OPTICAL-PROPERTIES OF SOL-GEL PROCESSED LEAD TITANATE THIN-FILMS

Polycrystalline PbTiO3 thin films having layered perovskite structure were fabricated by a sol-gel (spin coating) processing method. The sub strates used were fused silica and stainless-steel, Surface morphology of the films was studied with scanning electron microscopy (SEM). The effect of post-deposition annealing on the electrical and structural properties were analyzed. Crystalline phase of PbTiO3 can only be obta ined when the annealing temperature is higher than 500 degrees C. The electrical measurements were conducted on metal-film-metal capacitors. Films annealed at 600 degrees C exhibited crystallinity with perovski te phase: a dielectric constant of 132 and a dissipation factor of 0.0 39 at 1kHz. I-V characteristics were found to be ohmic at low fields a nd space charge limited, controlled by traps at high fields. Transmiss ion spectra of the films deposited on fused silica were recorded and f rom this, refractive index, extinction coefficient and thickness of th e films were calculated. The standard deviation of the thickness was f ound to be 18.8 nm. The dispersion curve for the refractive index 'n' is fairly fiat beyond 500 nm and rises rapidly towards shorter wavelen gth region, showing the typical shape of dispersion curve near an inte rband transition. The refractive index was found to be in the range 2. 00-2.20 for different wavelengths (300 to 900 nm).